Numbers / 313

The Number 313

313 is prime: only 1 and 313 divide it evenly; the next prime after 313 is 317. 313's proper divisors total just 1, 312 short of 313, the deficient case most of 313's neighbors share too. 313 is also a palindrome, since 313 reads identically forwards and backwards. 313 has a digit sum of 7; for 313, the digital root works out to 7. 313 shares no factor with 2-12; 313's own divisors start beyond that range. 313 is 100111001 in binary and 139 in hex; as a Roman numeral it's CCCXIII.