Revelation 13:18

Here is wisdom. Let him that hath understanding&c. "The terms of the challenge serve at once to shew that the feat proposed is possible, and that it is difficult." (Alford.)

the number of a man Comparing Revelation 21:17, it appears that these words mean "is reckoned simply, by an ordinary human method."

Six hundred threescore and six The reading 616 is ancient, but certainly wrong: and it is not impossible that the repetition (which must strike every one in the words, though the Greek figuresdo not suggest it like the Arabic) of the number 6 is significant: it approximates to, but falls short of, the sacred 7. Certainly we get no help by referring to 1 Kings 10:14 where the number is probably arrived at, by calculating that Solomon got 2000 talents every threeyears: cf. 1 Kings 10:22.