Numbers / 309

The Number 309

309 is composite: factorization 3 × 103. That gives 309 exactly 4 divisors: 1, 3, 103, 309. 309's proper divisors total just 107, 202 short of 309, the deficient case most of 309's neighbors share too. 309 has a digit sum of 12; for 309, the digital root works out to 3. 309: 3 all divide 309 evenly, out of 2-12. 309 is 100110101 in binary and 135 in hex; as a Roman numeral it's CCCIX.