Number
321 in Roman numerals
321 is written CCCXXI
Type any other number or numeral below to convert it.
Above 3,999? Type the barred part in brackets, e.g. (IV)CC = 4,200.
How CCCXXI is built
Roman numerals are written one decimal place at a time, largest first.
- CCChundreds · 3C written 3 times: 3 × 100 = 300.
- XXtens · 2X written 2 times: 2 × 10 = 20.
- Iones · 1I is 1.
300 + 20 + 1 = 321
No subtraction is needed here: every letter is the same size or smaller than the one before it, so you simply add them up.
About the number 321
- 321 is odd and can be split into prime factors: 3 × 107, or in Roman numerals III × CVII.
- CCCXXI has 6 letters. 396 of the numbers up to 1,000 have longer numerals.
Counting from 321 to 330
Every number from 321 to 330 starts CCCXX (320); only the ending changes.
| Number | Roman numeral |
|---|---|
| 321 | CCCXXI |
| 322 | CCCXXII |
| 323 | CCCXXIII |
| 324 | CCCXXIV |
| 325 | CCCXXV |
| 326 | CCCXXVI |
| 327 | CCCXXVII |
| 328 | CCCXXVIII |
| 329 | CCCXXIX |
| 330 | CCCXXX |