Numbers / 891

The Number 891

891 is composite: factorization 3^4 × 11. That gives 891 exactly 10 divisors: 1, 3, 9, 11, 27, 33, 81, 99, 297, 891. 891's proper divisors total just 561, 330 short of 891, the deficient case most of 891's neighbors share too. 891 has a digit sum of 18; for 891, the digital root works out to 9. 891: 3, 9, 11 all divide 891 evenly, out of 2-12. 891 is 1101111011 in binary and 37B in hex; as a Roman numeral it's DCCCXCI.