Numbers / 990

The Number 990

990 is composite: factorization 2 × 3^2 × 5 × 11. That gives 990 exactly 24 divisors: 1, 2, 3, 5, 6, 9, 10, 11, 15, 18, 22, 30, 33, 45, 55, 66, 90, 99, 110, 165, 198, 330, 495, 990. 990's proper divisors total 1818, 828 more than 990 itself, so 990 is abundant. 990 is also the 44th triangular number, the sum of 1 through 44. 990 has a digit sum of 18; for 990, the digital root works out to 9. 990: 2, 3, 5, 6, 9, 10, 11 all divide 990 evenly, out of 2-12. 990 is 1111011110 in binary and 3DE in hex; as a Roman numeral it's CMXC.