Actually, there is this whole deal that involves a thing called Jewish Numerology. In this the Jewish, or so I have been told, find holy meaning in numbers. For example:
7 - holy
40 - test and/or trial
3 - really
One less than (7 - 1 = 6/40 - 1 = 39) = Evil or incomplete
So, "666" can still be translated as the sign of the devil, seeing as he is supposed to be really evil, but the literal translation, which Regulith so kindly posted, shows it to be "616." Now, I don't believe in the devil, or Satan as some would wish I call him.