Numbers / 667

The Number 667

667 is composite: factorization 23 × 29. That gives 667 exactly 4 divisors: 1, 23, 29, 667. 667's proper divisors total just 53, 614 short of 667, the deficient case most of 667's neighbors share too. 667 has a digit sum of 19; for 667, the digital root works out to 1. 667 shares no factor with 2-12; 667's own divisors start beyond that range. 667 is 1010011011 in binary and 29B in hex; as a Roman numeral it's DCLXVII.