Numbers / 810

The Number 810

810 is composite: factorization 2 × 3^4 × 5. That gives 810 exactly 20 divisors: 1, 2, 3, 5, 6, 9, 10, 15, 18, 27, 30, 45, 54, 81, 90, 135, 162, 270, 405, 810. 810's proper divisors total 1368, 558 more than 810 itself, so 810 is abundant. 810 has a digit sum of 9; for 810, the digital root works out to 9. 810: 2, 3, 5, 6, 9, 10 all divide 810 evenly, out of 2-12. 810 is 1100101010 in binary and 32A in hex; as a Roman numeral it's DCCCX.