What is 24 written as a Roman numeral?

24 is written as the Roman numeral XXIV.

Roman numerals use combinations of seven symbols: I, V, X, L, C, D, and M. The numeral XXIV breaks into XX, meaning 20, followed by IV, meaning 4. Together, 20 plus 4 equals 24.

The “IV” is an example of subtractive notation: I appears before V, so 1 is subtracted from 5. This differs from VI, which means 6 because the smaller symbol follows the larger one. A common mistake is writing XXIIII, an additive form used in some historical contexts, but XXIV is the standard modern notation.

Roman numerals remain common on clock faces, monarch names, book chapters, outlines, and the Super Bowl. The number 24 is also notable because it has eight positive divisors and is the smallest number divisible by each integer from 1 through 4.