odd, composite · 391st positive integer
The number 391
391 is an odd composite number. It is the 391st positive integer.
Quick reference
| Prime factorization | 17 × 23 |
| Divisors | 1, 17, 23, 391 |
| Binary | 110000111 |
| Hexadecimal | 0x187 |
| Roman numeral | CCCXCI |
| Digit sum | 13 |
| Properties | odd, composite |
Frequently asked
Is 391 a prime number?
No. 391 is composite. Its prime factorization is 17 × 23.
What are the factors of 391?
The factors (divisors) of 391 are 1, 17, 23, 391.
What is 391 in binary?
391 in binary is 110000111. In hexadecimal it's 187.
What is 391 as a Roman numeral?
391 in Roman numerals is CCCXCI.
What's the digit sum of 391?
Adding the digits of 391: 3 + 9 + 1 = 13.