6 is the only number the represents man. It symbolises the imperfections, labour, and weakness of man, as well as sin. Man was even created on the 6th day. The creation of the world wasnt complete until God took the seventh day to rest, implying that six days wasnt quite enough. There are, however, 66 books in the bible, and it is well known that the number 666 represents the unholy trinity or Satan, Antichrist, and the false prophet; all that is the antithesis of God.