To rightly understand the truth concerning the Number of the Beast, we need to look at its first mention in Scripture. The first mention of anything in Scripture, often refered to as the Principle of First Mention, means that the first mention often establishes the context by which we are to understand all further mentions. So let's look at where this 'mark' is first spoken of in Scripture.
We are all familiar with the story of Cain and Abel. Abel offered up a sacrifice unto God of a suckling lamb, and Cain offered up the fruits of his labours in the field and of his harvest of crops. God accepted Abel's offering, but not Cain's. Many have debated why Cain's offering was not accepted, seeing as meat (meal) offerings and first-fruit offerings were accepted offerings in the Temple.
I believe the answer lies in the point God is trying to make. Man was a fallen creature by now and no longer had the privilege of access to God except through sacrifice. Abel brought the prescribed sacrifice (ref. Gen. 3:21; Rev. 13:8), indicating his faith in the blood of the Lamb to come, the Saviour promised in Genesis 3:15. Cain, on the other hand, effectually denied this Saviour and offered up the fruits of his own labours from a ground that had been cursed for man's sake. Cain sought his acceptance through his own merits, rather than through faith. That is the essential reason for why Abel's offering was accepted and Cain's was not.
Cain, not understanding this (2 Cor. 4:4), sought vengeance against his brother. How often we try to avenge our disappointments with God by blaming others as the cause or source of our problem. His mother did it, as well as his father Adam. She blamed the serpent, Adam blamed both his wife and God. Now Cain is blaming his brother Abel. God attempts to reason with Cain and bring a halt to his madness, telling Cain it is in the power of his hand to resist the sin about to overtake him, but Cain will have nothing to do with it. Instead, he rises up against Abel and slays him in the field.
God meets with Cain and delivers His judgment against Cain. Cain is now cursed from the earth, and it will no longer bring forth for him. He will be a fugitive and a vagabond in the earth. Cain complains that this judgment against him is too much to bear. God is being unfair to him because now everyone will try to kill him. God now puts a mark on Cain, declaring that whosoever slays Cain, vengeance will be taken on him seven-fold.
It does not take much imagination or reflection to see in this story of Cain and Abel, the story of Satan, whether it be his fall before God, or his punishment for his deed in the garden of Eden, played out through living people. This is the origin of the mark of the beast.
Sympathy has at times been expressed for Cain, but there are a few salient points that need to be understood here. First, Cain was a murderer, the first (or the seed of the first, Satan) in Scripture. God could not permit this sin, which was to destroy his brother who was made in the image of God, unpunished. Second, Cain did not make any attempt to resist his murderous rage against Abel. Third, Cain was unrepentant of his sin, and when brought to correction, complained of his punishment, in essence calling God cruel, harsh, and unfair. Can you not see the effects of Satan's dominion over Cain at work? Cain gave place to the devil. God is telling us the end from the beginning. Cain is punished accordingly.
Now let's fast forward to the book of Revelation where the Number of the Beast is mentioned specifically.
"Here is wisdom. Let him that has understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six." - Rev. 13:18
All understanding of Scripture must be supported by the full body and counsel of Scripture. That is the standard rule for interpreting the meaning of Scripture. Going to outside resources and using them to back up or prove anyone's scriptural theory is going to meet with errors of interpretation based on individual bias and that we all tend to see what we want to see ... or not, as the case may be.
The key to interpreting this verse lies in the last half of this verse: "for it is the number of a man...". Who is that man? Rather than trying to figure out whose name adds up to the required "666," as we have spent much time in doing, let's re-examine what this verse actually says. The KJV says that the number of the beast is the number "of a man." Other translations say, "it is a man's number." This verse could just as easily and perhaps more accurately have been interpreted, "it is the number of man..." Let me explain why. And to do this we need to go back to Genesis once again.
First, a little science, seeing as we are dealing with a material man, in a material world. We ought to know something of the material of which we are made.
Carbon is a vital component of all known living systems, and without it, life as we know it could not exist. Carbon is formed through a triple collision of alpha particles and is abundant in the sun, stars, comets and the atmostphere of most plants. Carbon can also be manufactured by burning organic material in insufficient oxygen.
*all facts from Wikipedia, http://en.wikipedia.org/Carbon. If you go to this page you will find an endless number of fascinating correspondences between man and carbon.
There are a couple of interesting aspects to this carbon we need to pay attention to. The first is that it is formed of a "triple" collision of alpha particles. Does anyone else see allusions to the Godhead of Father, Son and Holy Spirit here?
Carbon is also formed through the burning of organic material in insufficient oxygen. "Our God is a consuming fire," (Heb. 12:29). Man separated from God 'burns' with insufficient oxygen to be fully consumed by the glory of God. When man sinned, he died. His fire went out. Incomplete combustion (Gen. 2:17, 3:16; Eph. 2:12). These allusions will either register with you or not. But just keep them in mind. They will register at some point.
According to every biology textbook on the planet, man is considered a carbon-based lifeform. Carbon is the fourth most abundant element in the earth. Man was formed from the earth, and every element in it is represented in his bodily makeup. Earth itself exists in a carbon-cycle that moves carbon around through the earth, including in the plants and animals. Carbon forms the complex molecules such as DNA that make life on earth possible.
The atomic weight of Carbon is 6. That means that Carbon is made up of:

The Number of the Beast is the number of a man, or "the number of man" and that number is six hundred and threescore and six. "666." Man, as formed from the dust of the ground, a mere carbon-based lifeform, as a whole, represents the number of the beast. And while there will always be a specific individual appointed to fulfil this role in the last days, who he is isn't anywhere near as important as ensuring that we are not of that number ourselves.
God created the beasts of the earth and every creeping thing on it on the sixth day of creation. God also created man on the sixth day, after he created the beasts. The Beasts are older then man, as Cain was older then Abel. Though he was a twin brother, Cain was the eldest. Beasts and man were formed on the same day, yet beasts were the eldest. The only thing that separates a man from a beast is that man alone was made in the image of God with the capacity of self-awareness and the ability to 'know' God. A beast, no matter how well trained, how skilful or adept lacks the capacity to live beyond its own instincts for survival.
Man that is in honour and understands not, is like the beasts that perish - Ps. 49:20)
Get wisdom, and with all thy getting, get understanding - Prov. 4:4
Man, without understanding or knowledge of God in Christ, is like the beasts, made of the same stuff, created the same day.
Behold, the days come, saith the LORD, that I will sow the house of Israel and the house of Judah with the seed of man, and with the seed of beast. - Jer. 31:27
God is talking about people here. God showed this in his judgment of Nebuchadnezzar, who, after boasting of his own glory and magnificence, despite being forewarned and pleaded with to change his ways, didn't and was driven from among men, to dwell with the beasts, and eat grass as the beasts, until he knew that the most High rules in the kingdom of men, and gives it to whomsoever He will (Dan. 4:32). I trust that Scripture itself has proven the point that man without understanding is nothing more than like the beasts of the field.
So what changes man from the 'beast' bearing the number "666"? The answer is, through our salvation in Jesus Christ, accomplished in two ways. Take a look at this, for I do not believe it is mere coincidence.
James Strong indexed every word of the original manuscripts in the original language and assigned them a number. They are called "Strong's numbers." Every word of the KJV English translation of these manuscripts was indexed and the assigned Strong's numbers of the original languages were assigned, so that anyone could look up an English word in Scripture, and find the Greek or Hebrew word that was used in the original manuscript.
The Hebrew Word for righteousness was assigned the number,

The additional of that extra "6" changes man from beast to a man of understanding, able to commune with God, in His righteousness. Our own righteousness will not do, and this is why. All our own righteousness can do is clean the outside of the cup. It is quite simple when you stop to think about it. A dirty rag cannot make anything clean. It may look clean, but a dirty rag can only make other things it touches dirty. Only a pure and holy thing can make something dirty, clean. And all of us are 'dirty' so to speak through the sin and fall of Adam.
It takes the power of the Creator, the Almighty God, to change what we became with Adam's fall from His grace. And God did just that, in sending Christ His Son to die for us, nailing the body of sin, the old Adamic nature to the cross, dying for us, as us, so we could live unto God, through Him. When, by faith, we choose to be baptized into His death, we lose our old Adamic or beast nature. That nature is now covered by the righteousness of Christ and His merits, hence our number now becomes 6666.
Now that we are made righteous through Christ, it becomes incumbent upon us to pursue holiness until we are "one" with God. It is interesting to note that the Hebrew word assigned the Strong's number "6" is abad. It means to perish, or destroy. Only through our faith in Christ's sacrifice do we effectively 'perish' to our old Adamic nature, to be raised up to a new life in Him, to live unto God His way, through the strength of the indwelling Christ, and the leading and instruction of the Holy Spirit.
Those who do not choose to believe in Christ, to trust in the merits of His sacrifice, death and resurrection, indicating that the Father accepted His sacrificial offering for us, retain that dreaded number 666. There is no way to change it apart from faith in Christ the Messiah. It is for this reason that most of mankind already bears the mark of Cain, the mark or number of the Beast.
It is also interesting to note that one of the distinctive purposes of this mark is that it is what will allow a man to buy or sell. It is the mark of trade. Only those who bear that mark, whether in their hand or their forehead, will be able to trade.
It is written in Scripture that you cannot serve God and mammon. You have to choose to serve one or the other. When you serve God, He becomes your provider, your provision, and to choose God and eternal life in Christ over what this world can offer is what this mark of the beast is about to settle. When the crunch comes, which one will you serve?
In this, mankind is given one last opportunity to stand for God. He can choose to die a martyr rather than take the number and suffer the punishments meted to those who will not take the number. Remember, you will not be able to buy, or sell. That means you will not be able to receive wages, nor pay for your food, your housing, your clothing or any other thing those wages would obtain.
The Word of God says again, Seek ye first the kingdom of God, and His righteousness, and all these things will be added unto you. (Matt. 6:33). God will provide for all these things for you. Furthermore, if you actually seek His righteousness, I doubt you will even care for the things of this world. Let the devil have it all as long as you have God.
There is another reference to this "Beast" and it is in Daniel, where he refers to the "fourth kingdom" that will rise up, different from all the ones that had preceded it. I believe this fourth kingdom is the 'kingdom' of artificial intelligence. Depending on how you see it, or rather how your use it (or it uses you), could also be this "Beast" spoken of. One of the primary uses of AI and technology, is to lull people into not thinking for themselves. It has perhaps been one of the most useless tools ever invented, seeing as we have to keep finding ways to make it useful for us, to the point that we, as thinking, reasoning beings made in the image of God, are being reduced to automatons, obeying what we are told, thinking what we are told to think, believing what we are being told to believe. You can see it all around us: phone zombies, people who are no longer able to think or do for themseves, people who have handed control of their lives over to their "smart" devices. We had more wisdom and ability to spot a liar, a scam, and a bad influence before all this technology came into the popular domain. While there may be some very good uses that it is put to, we no longer rely on God, and, if we were honest about it all, how would we evven know if they are wrong in what it is this Artificial Intelligence is telling us? If a machine builds a machine that builds a machine that we have no idea how to build ourselves, how can you ever control it, fix it, or, worst case scenario, stop it?
Even science is telling us that our brains are being rewired through our use of this technological medium, until I am certain, we will be no better than those idols who have mouths but speak not, eyes but see not, and ears that hear not, that must be carried because they cannot go, and so on. (AI insight from video AI, 666 and the AntiChrist; see it here)
The days that are coming are to prepare you for this last and final opportunity to stand for Christ. You can let the Holy Spirit put you on a virtual cross, to die to self, and all dependence on this world, suffering as did Christ for the choices it will compel you to make against the desires of the flesh and this world,and become one (6) in Him, or you can do it when the time comes to take that number. But be aware. What you will not do now, chances are, you will be unable to do then. This is why the actual taking of that physical number will only be the final evidence that you have chosen to live for yourself and your own needs. Heed the Word now while you can.
If you seek to save your life (in this world), you will lose it (your life in Christ). But if you seek to lose your life (in this world), for His sake and the Gospel's, you will save it unto eternal life. (Matthew 16:25, Mark 8:35, Luke 9:24, and John 12:25)