odd, prime, palindrome · 191st positive integer
The number 191
191 is an odd prime number. It is the 191st positive integer.
Quick reference
| Prime factorization | 191 (prime) |
| Divisors | 1, 191 |
| Binary | 10111111 |
| Hexadecimal | 0xBF |
| Roman numeral | CXCI |
| Digit sum | 11 |
| Properties | odd, prime, palindrome |
Reading 191 in NumGrid context
191 is one of the data points covered by this site’s integer properties and number-guessing puzzles dataset. The detail above comes directly from classical number theory plus NumGrid solver-derived puzzle statistics; the context that follows situates the headline numbers against the broader distribution across positive integers within the NumGrid target pool.
Every number on this page links back to classical number theory plus NumGrid solver-derived puzzle statistics; the methodology page describes the inputs, refresh cadence, and known limitations of the underlying data product.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for 191’s peers within positive integers within the NumGrid target pool. A single-entity reading without peer context can be misleading when an entity is an outlier on one axis but typical on another.
Frequently asked
Is 191 a prime number?
Yes. 191 is prime — its only divisors are 1 and itself.
What are the factors of 191?
The factors (divisors) of 191 are 1, 191.
What is 191 in binary?
191 in binary is 10111111. In hexadecimal it's BF.
What is 191 as a Roman numeral?
191 in Roman numerals is CXCI.
What's the digit sum of 191?
Adding the digits of 191: 1 + 9 + 1 = 11.