Numbers / 531

The Number 531

531 is composite: factorization 3^2 × 59. That gives 531 exactly 6 divisors: 1, 3, 9, 59, 177, 531. 531's proper divisors total just 249, 282 short of 531, the deficient case most of 531's neighbors share too. 531 has a digit sum of 9; for 531, the digital root works out to 9. 531: 3, 9 all divide 531 evenly, out of 2-12. 531 is 1000010011 in binary and 213 in hex; as a Roman numeral it's DXXXI.