Numbers / 549

The Number 549

549 is composite: factorization 3^2 × 61. That gives 549 exactly 6 divisors: 1, 3, 9, 61, 183, 549. 549's proper divisors total just 257, 292 short of 549, the deficient case most of 549's neighbors share too. 549 has a digit sum of 18; for 549, the digital root works out to 9. 549: 3, 9 all divide 549 evenly, out of 2-12. 549 is 1000100101 in binary and 225 in hex; as a Roman numeral it's DXLIX.