Numbers / 209

The Number 209

209 is composite: factorization 11 × 19. That gives 209 exactly 4 divisors: 1, 11, 19, 209. 209's proper divisors total just 31, 178 short of 209, the deficient case most of 209's neighbors share too. 209 has a digit sum of 11; for 209, the digital root works out to 2. 209: 11 all divide 209 evenly, out of 2-12. 209 is 11010001 in binary and D1 in hex; as a Roman numeral it's CCIX.