Numbers / 131

The Number 131

131 is prime: only 1 and 131 divide it evenly; the next prime after 131 is 137. 131's proper divisors total just 1, 130 short of 131, the deficient case most of 131's neighbors share too. 131 is also a palindrome, since 131 reads identically forwards and backwards. 131 has a digit sum of 5; for 131, the digital root works out to 5. 131 shares no factor with 2-12; 131's own divisors start beyond that range. 131 is 10000011 in binary and 83 in hex; as a Roman numeral it's CXXXI.