Numbers / 17

The Number 17

17 is prime: only 1 and 17 divide it evenly; the next prime after 17 is 19. 17's proper divisors total just 1, 16 short of 17, the deficient case most of 17's neighbors share too. 17 has a digit sum of 8; for 17, the digital root works out to 8. 17 shares no factor with 2-12; 17's own divisors start beyond that range. 17 is 10001 in binary and 11 in hex; as a Roman numeral it's XVII.