Numbers / 157

The Number 157

157 is prime: only 1 and 157 divide it evenly; the next prime after 157 is 163. 157's proper divisors total just 1, 156 short of 157, the deficient case most of 157's neighbors share too. 157 has a digit sum of 13; for 157, the digital root works out to 4. 157 shares no factor with 2-12; 157's own divisors start beyond that range. 157 is 10011101 in binary and 9D in hex; as a Roman numeral it's CLVII.