Numbers / 709

The Number 709

709 is prime: only 1 and 709 divide it evenly; the next prime after 709 is 719. 709's proper divisors total just 1, 708 short of 709, the deficient case most of 709's neighbors share too. 709 has a digit sum of 16; for 709, the digital root works out to 7. 709 shares no factor with 2-12; 709's own divisors start beyond that range. 709 is 1011000101 in binary and 2C5 in hex; as a Roman numeral it's DCCIX.