odd, composite, triangular · 561st positive integer
The number 561
561 is an odd composite number. It is the 561st positive integer.
Quick reference
| Prime factorization | 3 × 11 × 17 |
| Divisors | 1, 3, 11, 17, 33, 51, 187, 561 |
| Binary | 1000110001 |
| Hexadecimal | 0x231 |
| Roman numeral | DLXI |
| Digit sum | 12 |
| Properties | odd, composite, triangular |
Reading 561 in NumGrid context
561 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.
For readers using this page as a decision input, the related-entity pages elsewhere on the site provide the comparison set. The most useful comparison for 561 is typically a peer within positive integers within the NumGrid target pool with similar size, similar exposure, or similar geography — not the national-level summary alone.
Frequently asked
Is 561 a prime number?
No. 561 is composite. Its prime factorization is 3 × 11 × 17.
What are the factors of 561?
The factors (divisors) of 561 are 1, 3, 11, 17, 33, 51, 187, 561.
What is 561 in binary?
561 in binary is 1000110001. In hexadecimal it's 231.
What is 561 as a Roman numeral?
561 in Roman numerals is DLXI.
What's the digit sum of 561?
Adding the digits of 561: 5 + 6 + 1 = 12.