Numbers / 851

The Number 851

851 is composite: factorization 23 × 37. That gives 851 exactly 4 divisors: 1, 23, 37, 851. 851's proper divisors total just 61, 790 short of 851, the deficient case most of 851's neighbors share too. 851 has a digit sum of 14; for 851, the digital root works out to 5. 851 shares no factor with 2-12; 851's own divisors start beyond that range. 851 is 1101010011 in binary and 353 in hex; as a Roman numeral it's DCCCLI.