Numbers / 515

The Number 515

515 is composite: factorization 5 × 103. That gives 515 exactly 4 divisors: 1, 5, 103, 515. 515's proper divisors total just 109, 406 short of 515, the deficient case most of 515's neighbors share too. 515 is also a palindrome, since 515 reads identically forwards and backwards. 515 has a digit sum of 11; for 515, the digital root works out to 2. 515: 5 all divide 515 evenly, out of 2-12. 515 is 1000000011 in binary and 203 in hex; as a Roman numeral it's DXV.