1421 in Roman numerals

1421 in Roman numerals is MCDXXI.

Pick any whole number from 1 to 3,999.

1421 = \text{MCDXXI}

How to work it out

1
Take the biggest Roman value that fits, write its letter, subtract it, and repeat.
2
Here: 1000 (M) + 400 (CD) + 10 (X) + 10 (X) + 1 (I) = 1421.
3
Joined together: MCDXXI. (Four of the same letter in a row is never used: 4 is IV, 9 is IX, 40 is XL, 90 is XC, 400 is CD, 900 is CM.)

What is 1421 in Roman numerals?

MCDXXI.

How do you read MCDXXI?

MCDXXI = 1000 + 400 + 10 + 10 + 1 = 1421.