21 in Roman Numerals
21
XXI
twenty-one
How XXI is formed
| Place | Value | Symbols |
|---|---|---|
| Tens | 20 | XX |
| Units | 1 | I |
| Total | 21 | XXI |
XXI is written one place at a time, from the largest to the smallest: XX (20) + I (1) = 21.
Where you'll see XXI
Super Bowl XXI was played on January 25, 1987 at Rose Bowl in Pasadena: the New York Giants beat the Denver Broncos 39–20.
The Games of the XXI Olympiad were held in Montreal in 1976.
The XXI Olympic Winter Games were held in Vancouver in 2010.
Using XXI
As the day of a date, 21 is XXI: December 21 is XII.XXI written month.day, or XXI.XII written day.month. Convert a full date
Numbers near 21
Properties of 21
- Prime factors
- 3 × 7
- Divisors
- 1, 3, 7, 21
- Even or odd
- Odd
- Prime number
- No
- Letters in XXI
- 3
21,000 in Roman numerals
With a bar over it (vinculum), X̅X̅I̅ means 21 × 1,000 = 21,000. How Roman numerals work