While 666 is called the "number of the beast" in most manuscripts of Revelation 13:18, a fragment of papyrus 115 gives the number as 616.
They both have merit for being right and there are a lot of blogs devoted to this subject. I think that the powers that be have hedged their bets on both these numbers. You have probably seen the logos that have 666 in them.
What do we find for 616?
I think that number might be used more than we think.
In DrudgeReport today they had a link to http://www.laweekly.com/news/satanists-plan-to-celebrate-6-6-16-in-la-6963630 an article about how Satanists plan to celebrate on 6/6/16 for 666 but maybe they are celebrating 616. The article was pretty creepy.