140

140 = 2² x 5 x 7.

140 has a unique representation as a sum of three squares: 140 = 2² + 6² + 10².

140 is a square pyramidal number. It is the sum of the first seven squares: 140 = 1² + 2² + 3² + 4² + 5² + 6² + 7².

140 is a harmonic divisor number.

140 Siwa is a large, dark asteroid discovered in 1874.

Source: Prime Curios!