Numbers / 331

The Number 331

331 is prime: only 1 and 331 divide it evenly; the next prime after 331 is 337. 331's proper divisors total just 1, 330 short of 331, the deficient case most of 331's neighbors share too. 331 has a digit sum of 7; for 331, the digital root works out to 7. 331 shares no factor with 2-12; 331's own divisors start beyond that range. 331 is 101001011 in binary and 14B in hex; as a Roman numeral it's CCCXXXI.