Numbers / 581

The Number 581

581 is composite: factorization 7 × 83. That gives 581 exactly 4 divisors: 1, 7, 83, 581. 581's proper divisors total just 91, 490 short of 581, the deficient case most of 581's neighbors share too. 581 has a digit sum of 14; for 581, the digital root works out to 5. 581: 7 all divide 581 evenly, out of 2-12. 581 is 1001000101 in binary and 245 in hex; as a Roman numeral it's DLXXXI.