Numbers / 20

The Number 20

20 is composite: factorization 2^2 × 5. That gives 20 exactly 6 divisors: 1, 2, 4, 5, 10, 20. 20's proper divisors total 22, 2 more than 20 itself, so 20 is abundant. 20 has a digit sum of 2; for 20, the digital root works out to 2. 20: 2, 4, 5, 10 all divide 20 evenly, out of 2-12. 20 is 10100 in binary and 14 in hex; as a Roman numeral it's XX.