694

694 = 2 x 347.

694 is a centered triangular number (A005448).

694 and 695 are consecutive semiprimes (A070552). 694 is a semiprime with only semiprime digits (A107342).

694 is 1010110110 in base (binary). 694 is the smallest pandigital number in base 5 (10234), containing all possible digits.

694 is the number of different arrangements (up to rotation and reflection) of 7 non-attacking rooks on a 7 x 7 chessboard.

694 is the number of partitions of 34 in which no part occurs only once (A007690).

Source: Number Gossip