688

688 = 2⁴ x 43.

688 has a unique representation as a sum of three squares: 688 = 12² + 12² + 20².

688 is a vampire number because there exists a factorization of 688 using 688's digits: 688 = 86 x 8. It is also a Friedman number.

688 is 221111 in base 3, 2002 in base 7, 844 in base 9, 494 in base 12, and 224 in base 18.

The 688 Club was a popular alternative music venue in Atlanta, Georgia.

Source: Number Gossip