Numbers / 89

The Number 89

89 is prime: only 1 and 89 divide it evenly; the next prime after 89 is 97. 89's proper divisors total just 1, 88 short of 89, the deficient case most of 89's neighbors share too. 89 is also a Fibonacci number, since 55 + 34 = 89. 89 has a digit sum of 17; for 89, the digital root works out to 8. 89 shares no factor with 2-12; 89's own divisors start beyond that range. 89 is 1011001 in binary and 59 in hex; as a Roman numeral it's LXXXIX.