Numbers / 644
The Number 644
644 is composite: factorization 2^2 × 7 × 23. That gives 644 exactly 12 divisors: 1, 2, 4, 7, 14, 23, 28, 46, 92, 161, 322, 644. 644's proper divisors total 700, 56 more than 644 itself, so 644 is abundant. 644 has a digit sum of 14; for 644, the digital root works out to 5. 644: 2, 4, 7 all divide 644 evenly, out of 2-12. 644 is 1010000100 in binary and 284 in hex; as a Roman numeral it's DCXLIV.