Letters and Words are NOT INCONSEQUENTIAL! What does 666 mean According to the Greek Letters?

And he causes all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads: And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name. Here is wisdom. Let him that has understanding(it is a mystery) calculate the number of the beast: for it is the number of a man; and his number is χξς. REVELATION 13:16-18 את CEPHER

“For the mystery(difficult to understand) of lawlessness is already at work; only He who now restrains will do so until He is taken out of the way.” 2 Thessalonians 2:7