But we know that the number 666 is the beast
The number refer to the beast's name. In Greek and Hebrew they didn't have distinct symbols to write out numbers, but used the letters from their alphabets. So numeric values were assigned to letters. So, for example, in Greek the Apostle Paul's name is Παύλος (Paulos), each letter has a numeric value and can be added up together,
Π = 80
α = 1
ύ = 400
λ = 30
ο = 70
ς = 200
80+1+400+30+70+200 = 781
And thus we could say that the number of Paul's name is 781.
In the same way what John writes in the Revelation is that the number of the beast's name (what his name adds up to) is six hundred and sixty-six (666).
666 isn't a magically evil number. It's simply what the numerical value of the name of the beast equals. John provides us with this to give his readers a clue as to who he is talking about.
It seems more "scary" because it's three sixes, but this is only the case when using Arabic numerals. The same number written in Roman numerals is DCLXVI (500+100+50+10+5+1). In Greek numerals the number is ΧΞϚ (600+60+6).
You can even see this by looking at the ancient manuscripts of the Book of the Revelation,
There's nothing magical or mystical about numbers. 8 isn't a magical number, and it doesn't become more powerful or something by adding more 8's to it. The number 8 does have historic use in Christianity as symbolically indicating redemption and renewal. Early Christians spoke of the day Christ rose from the dead as the new "8th day" of creation, the new day of new life. As such Christian art and architecture has often used 8 in this way, for example churches were often historically built with 8 sides, baptismal fonts were likewise 8-sided. But that's just a subtle nod to the symbolism. It's not anything more special about it than the use of the number 12 to represent the twelve tribes of Israel and the twelve apostles.
Numbers don't have any power, for good or for evil. They are just numbers. Numbers can be assigned symbolic value by human beings, but that's something we do. For example as Christians we often use the number 3 to signify the Trinity, or the number 2 to signify the two natures of Jesus Christ, the number 5 historically was used to represent the five wounds of Christ. That doesn't make these numbers mystical, only that we have chosen to incorporate symbolic value to some numbers. The same way shapes and other symbols gain meaning by their use. There's nothing mystical about two perpendicular lines intersecting one another, but in Christianity this is the symbol of the cross, and the obvious importance of the cross in Christianity can't be underestimated. In the same way the use of fire or a dove as symbols signifying the Holy Spirit. A lamb or good shepherd is used to symbolically represent Jesus. Etc.
But there's nothing magical about doves, or fire, or lambs, or shepherds; we simply use these things as symbols to signify certain aspects of our faith.
A good example of how important context is for symbols is St. Peter's cross. It is an upside-down cross, for many people the upside-down cross is viewed as evil, even satanic, because it is a desecrated cross. But, in fact, the traditional symbol for St. Peter the Apostle is an upside-down cross, because Peter was martyred by being crucified upside-down, according to tradition he requested that he be crucified upside-down because he did not feel himself worthy to be crucified in the same manner as his Lord and Savior. So St. Peter's cross is not a desecrated Christian cross, but is instead a symbol of the Apostle Peter; in the same way that an X-shaped cross is a symbol for the Apostle Andrew who was crucified on an X-shaped cross as a martyr for Christ. Context is important, things mean what they mean only within the context they are used.
So just because you see something that may in some contexts mean one thing, does not mean they always mean that. Just because a building has an 8 in its mailing address doesn't mean anything, it just means it has an 8 in its mailing address. If there is an address that is 666, there's nothing evil about that, it's just the number that comes after 665 and before 667. It only has meaning when it is meant to have meaning, based on context.
-CryptoLutheran
