Number reference
216 explained.
216: two hundred sixteen, composite, perfect cube; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- two hundred sixteen
- Classification
- composite
- Factors
- 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 27, 36, 54, 72, 108, 216
- Prime factorization
- 2 × 2 × 2 × 3 × 3 × 3
- Square root
- 14.696938
- Cube root
- 6
- Binary
- 11011000
- Octal
- 330
- Hexadecimal
- D8
- Roman numeral
- CCXVI
- Digit sum
- 9
- Digital root
- 9
What makes 216 notable
- Perfect cube. 216 = 6³, so a cube of edge 6 has a volume of 216.
216 in everyday use
Two hundred sixteen is six cubed, and so it is the number of outcomes when three dice are thrown, since each die has six faces. Early web designers knew it as the size of the web-safe palette: six evenly spaced levels of red, green, and blue give 216 colours that displayed correctly on the 256-colour monitors of the 1990s. In Plato's Republic a notoriously obscure passage describes a "geometrical number" that many commentators have identified as 216, the cube of six.
The number is the smallest cube that is itself the sum of three cubes: 3³ + 4³ + 5³ = 27 + 64 + 125 = 216, extending the 3-4-5 triangle into a third dimension. Factored, it is 2³ × 3³, so its divisors are the sixteen numbers of the form 2ᵃ3ᵇ with each exponent between 0 and 3. Its digit sum is 9, its digits multiply to 12, and it is 11011000 in binary.
Nearby numbers
How to read this page
The factor list shows every way 216 splits into equal whole-number groups — 16 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 216 for contexts that do not use decimal.
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