Numbers / 823

The Number 823

823 is prime: only 1 and 823 divide it evenly; the next prime after 823 is 827. 823's proper divisors total just 1, 822 short of 823, the deficient case most of 823's neighbors share too. 823 has a digit sum of 13; for 823, the digital root works out to 4. 823 shares no factor with 2-12; 823's own divisors start beyond that range. 823 is 1100110111 in binary and 337 in hex; as a Roman numeral it's DCCCXXIII.