Numbers / 688

The Number 688

688 is composite: factorization 2^4 × 43. That gives 688 exactly 10 divisors: 1, 2, 4, 8, 16, 43, 86, 172, 344, 688. 688's proper divisors total just 676, 12 short of 688, the deficient case most of 688's neighbors share too. 688 has a digit sum of 22; for 688, the digital root works out to 4. 688: 2, 4, 8 all divide 688 evenly, out of 2-12. 688 is 1010110000 in binary and 2B0 in hex; as a Roman numeral it's DCLXXXVIII.