Numbers / 397

The Number 397

397 is prime: only 1 and 397 divide it evenly; the next prime after 397 is 401. 397's proper divisors total just 1, 396 short of 397, the deficient case most of 397's neighbors share too. 397 has a digit sum of 19; for 397, the digital root works out to 1. 397 shares no factor with 2-12; 397's own divisors start beyond that range. 397 is 110001101 in binary and 18D in hex; as a Roman numeral it's CCCXCVII.