Numbers / 123

The Number 123

123 is composite: factorization 3 × 41. That gives 123 exactly 4 divisors: 1, 3, 41, 123. 123's proper divisors total just 45, 78 short of 123, the deficient case most of 123's neighbors share too. 123 has a digit sum of 6; for 123, the digital root works out to 6. 123: 3 all divide 123 evenly, out of 2-12. 123 is 1111011 in binary and 7B in hex; as a Roman numeral it's CXXIII.