724

724 = 2² x 181.

724 has a representation as a sum of two squares: 724 = 18² + 20².

724 divides 19⁴ - 1.

724 is the number of perfect connected undirected simple graphs on seven nodes.

724 is the number of different arrangements of 10 non-attacking queens on a 10 x 10 chessboard.

724 Hapag is an asteroid discovered in 1911, lost, then rediscovered in 1988.

Source: What's Special About This Number?