Numbers / 22

The Number 22

22 is composite: factorization 2 × 11. That gives 22 exactly 4 divisors: 1, 2, 11, 22. 22's proper divisors total just 14, 8 short of 22, the deficient case most of 22's neighbors share too. 22 is also a palindrome, since 22 reads identically forwards and backwards. 22 has a digit sum of 4; for 22, the digital root works out to 4. 22: 2, 11 all divide 22 evenly, out of 2-12. 22 is 10110 in binary and 16 in hex; as a Roman numeral it's XXII.