Numbers / 87

The Number 87

87 is composite: factorization 3 × 29. That gives 87 exactly 4 divisors: 1, 3, 29, 87. 87's proper divisors total just 33, 54 short of 87, the deficient case most of 87's neighbors share too. 87 has a digit sum of 15; for 87, the digital root works out to 6. 87: 3 all divide 87 evenly, out of 2-12. 87 is 1010111 in binary and 57 in hex; as a Roman numeral it's LXXXVII.