odd, composite · 221st positive integer
The number 221
221 is an odd composite number. It is the 221st positive integer.
Quick reference
| Prime factorization | 13 × 17 |
| Divisors | 1, 13, 17, 221 |
| Binary | 11011101 |
| Hexadecimal | 0xDD |
| Roman numeral | CCXXI |
| Digit sum | 5 |
| Properties | odd, composite |
Reading 221 in NumGrid context
For 221, the underlying data on this page comes from classical number theory plus NumGrid solver-derived puzzle statistics. The breakdown above is the federal record; the paragraphs below add the per-entity context that makes the headline numbers usable for a real decision rather than just a data lookup.
The methodology behind every numeric value on this page is publicly documented on the classical number theory plus NumGrid solver-derived puzzle statistics portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for 221’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 221 a prime number?
No. 221 is composite. Its prime factorization is 13 × 17.
What are the factors of 221?
The factors (divisors) of 221 are 1, 13, 17, 221.
What is 221 in binary?
221 in binary is 11011101. In hexadecimal it's DD.
What is 221 as a Roman numeral?
221 in Roman numerals is CCXXI.
What's the digit sum of 221?
Adding the digits of 221: 2 + 2 + 1 = 5.