For the record, the sign of the beast is probably 616 not 666. Of course to satisfy people’s devil interests, Wikipedia has notes on the Number of the Beast. The number 666 is so powerful that it causes such stupidity as renaming highways. US Route 666 was named in 1926 and had no problems for 77 years but in 2003 it was renamed to US Route 491.
A fragment from the oldest surviving copy of the New Testament, dating to the Third century, gives the more mundane 616 as the mark of the Antichrist.
…the discovery appears to spell the end of 666 as the devil’s prime number
…more conventional versions of the Bible give 666 as the “number of the beast,” or the sign of the anti-Christ whose coming is predicted in the book’s apocalyptic verses, the older version uses the Greek letters signifying 616.[Source, Religion News Blog, Beast’s real mark devalued to 616?]