21 in Roman numerals is XXI. Read from left to right: X (10) + X (10) + I (1) = 21.
How to write 21 in Roman numerals
Break 21 into thousands, hundreds, tens and ones, then write each part with the largest symbols first:
- 20 (tens) = XX
- 1 (ones) = I
Join them: XXI.
XXI only adds symbols from largest to smallest, with no subtraction pairs.
Roman numerals near 21
21 in words
21 is written twenty-one in words (see 21 in words), and इक्कीस in Hindi. Its ordinal form is 21st, written twenty-first.
Where you see Roman numerals
Roman numerals still appear on clock faces, in chapter and class numbers, in the names of kings and events, and in exam question numbering. For the full list of symbols and rules, see Roman numerals and the 1 to 100 chart.
Questions people ask
What is 21 in Roman numerals?
21 in Roman numerals is XXI.
What number is XXI?
XXI is 21: 10 + 10 + 1 = 21.
How do you write 21 in Roman numbers?
Write each place value with its symbols and join them: X X I gives XXI.
What is 210 in Roman numerals?
210 is CCX.