Numbers / 65

The Number 65

65 is composite: factorization 5 × 13. That gives 65 exactly 4 divisors: 1, 5, 13, 65. 65's proper divisors total just 19, 46 short of 65, the deficient case most of 65's neighbors share too. 65 has a digit sum of 11; for 65, the digital root works out to 2. 65: 5 all divide 65 evenly, out of 2-12. 65 is 1000001 in binary and 41 in hex; as a Roman numeral it's LXV.