Numbers / 859

The Number 859

859 is prime: only 1 and 859 divide it evenly; the next prime after 859 is 863. 859's proper divisors total just 1, 858 short of 859, the deficient case most of 859's neighbors share too. 859 has a digit sum of 22; for 859, the digital root works out to 4. 859 shares no factor with 2-12; 859's own divisors start beyond that range. 859 is 1101011011 in binary and 35B in hex; as a Roman numeral it's DCCCLIX.