Numbers / 67

The Number 67

67 is prime: only 1 and 67 divide it evenly; the next prime after 67 is 71. 67's proper divisors total just 1, 66 short of 67, the deficient case most of 67's neighbors share too. 67 has a digit sum of 13; for 67, the digital root works out to 4. 67 shares no factor with 2-12; 67's own divisors start beyond that range. 67 is 1000011 in binary and 43 in hex; as a Roman numeral it's LXVII.