Numbers / 311

The Number 311

311 is prime: only 1 and 311 divide it evenly; the next prime after 311 is 313. 311's proper divisors total just 1, 310 short of 311, the deficient case most of 311's neighbors share too. 311 has a digit sum of 5; for 311, the digital root works out to 5. 311 shares no factor with 2-12; 311's own divisors start beyond that range. 311 is 100110111 in binary and 137 in hex; as a Roman numeral it's CCCXI.