Haven't you guys heard? Six, six, six is probably not the number of the beast.
Actually, from what I've read, it isn't. There are a couple of different disputes about that, but my favorite is that older scrolls show the number 616 instead of 666.
But no one corrects mistakes, no matter how scientific or analytic the proof is because 666 is just plain easy to remember and is what everyone is used to.
Just like how Jesus wasn't born on 1AD after all, but no one corrects that miscalculation because 1AD is easier to remember. (And it would force everyone to remake their calendars so that this year is actually only 2000.)
But in general, Christians just seem to make mistakes when it comes to numbers.
They also seem to be fairly bad at dealing with critical historical analysis. Such as there's some very strong evidence that this whole anti-christ thing concept was actually a Jewish-driven slight at the Romans. First at Caligula (616) and later changed at Nero (666). (Which also further supports the 616-666 discrepency being a factor of time.)
Just as "the mark of the beast" was actually a slight at the Romans for the Jewish merchants being forced to know Latin in order to do business under the heavy hand of the Roman empire. The mark of the beast being on the head and in the right hand is actually just a reference to knowing and being able to write in Latin.