401 in Roman Numerals
401
C (subtracted)DI
four hundred one
How CDI is formed
| Place | Value | Symbols |
|---|---|---|
| Hundreds | 400 | C (subtracted)D |
| Units | 1 | I |
| Total | 401 | CDI |
CDI is written one place at a time, from the largest to the smallest: CD (400) + I (1) = 401.
CD is the only subtraction: the C before the D takes away 100, so CD = 400.
Common mistakes
Wrong: CCCCI
Why isn't 401 written as CCCCI?
A symbol can't be repeated four times in a row. 400 is CD (500 − 100), not CCCC, so 401 is CDI.
Numbers near 401
Properties of 401
- Prime factors
- 401
- Divisors
- 1, 401
- Even or odd
- Odd
- Prime number
- Yes
- Letters in CDI
- 3
401 is a prime number: it can only be divided by 1 and by itself.
401,000 in Roman numerals
With a bar over it (vinculum), C̅D̅I̅ means 401 × 1,000 = 401,000. How Roman numerals work