656

656 = 2 x 2 x 2 x 2 x 41.

656 is 1010010000 in base 2 (binary). It is a palindrome in base 3 (220022) (A007633 and A014190), base 9 (808), and base 10 (656) (A029965).

656 has a representation as a sum of two squares: 656 = 16² + 20².

656 has 10 binary digits and 10 divisors (1, 2, 4, 8, 16, 41, 82, 164, 328, 656) (A135772).

656 plus the 656th prime produces a triangular number (A115882): 656 + 4909 = 5565.

Source: What's Special About This Number?