Numbers / 513

The Number 513

513 is composite: factorization 3^3 × 19. That gives 513 exactly 8 divisors: 1, 3, 9, 19, 27, 57, 171, 513. 513's proper divisors total just 287, 226 short of 513, the deficient case most of 513's neighbors share too. 513 has a digit sum of 9; for 513, the digital root works out to 9. 513: 3, 9 all divide 513 evenly, out of 2-12. 513 is 1000000001 in binary and 201 in hex; as a Roman numeral it's DXIII.