Numbers / 638

The Number 638

638 is composite: factorization 2 × 11 × 29. That gives 638 exactly 8 divisors: 1, 2, 11, 22, 29, 58, 319, 638. 638's proper divisors total just 442, 196 short of 638, the deficient case most of 638's neighbors share too. 638 has a digit sum of 17; for 638, the digital root works out to 8. 638: 2, 11 all divide 638 evenly, out of 2-12. 638 is 1001111110 in binary and 27E in hex; as a Roman numeral it's DCXXXVIII.