'Six' in the Bible

And the four beasts, having every one of them six wings, are full of eyes round about and inside: and without resting day and night, they say, Holy, holy, holy, Lord God, Ruler of all, who was and is and is to come.

Here is wisdom. He who has knowledge let him get the number of the beast; because it is the number of a man: and his number is Six hundred and sixty-six.