Numbers / 679

The Number 679

679 is composite: factorization 7 × 97. That gives 679 exactly 4 divisors: 1, 7, 97, 679. 679's proper divisors total just 105, 574 short of 679, the deficient case most of 679's neighbors share too. 679 has a digit sum of 22; for 679, the digital root works out to 4. 679: 7 all divide 679 evenly, out of 2-12. 679 is 1010100111 in binary and 2A7 in hex; as a Roman numeral it's DCLXXIX.