Number reference
64 explained.
64: sixty-four, composite, power of two; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- sixty-four
- Classification
- composite
- Factors
- 1, 2, 4, 8, 16, 32, 64
- Prime factorization
- 2 × 2 × 2 × 2 × 2 × 2
- Square root
- 8
- Cube root
- 4
- Binary
- 1000000
- Octal
- 100
- Hexadecimal
- 40
- Roman numeral
- LXIV
- Digit sum
- 10
- Digital root
- 1
What makes 64 notable
- Power of two. 64 = 2^6, which is why it shows up in memory sizes, image dimensions, and anything that repeatedly halves or doubles.
- Perfect square. 64 = 8², so a square of side 8 has an area of 64.
- Perfect cube. 64 = 4³, so a cube of edge 4 has a volume of 64.
64 in everyday use
A chessboard has 64 squares, the I Ching has 64 hexagrams, and the genetic code has 64 codons, since three DNA letters chosen from four give 4 × 4 × 4 combinations. Sixty-four is the atomic number of gadolinium, used in MRI contrast agents. Modern processors are 64-bit, the Nintendo 64 console arrived in 1996, and Crayola's 64-crayon box with its built-in sharpener has been sold since 1958. The Beatles asked "will you still need me when I'm sixty-four?"
Sixty-four is the smallest number above one that is both a perfect square and a perfect cube: 8² and 4³, and also 2⁶. In binary it is 1000000, and in hexadecimal it is 40. Because it is a power of two, it has seven divisors, all powers of two themselves. It is also the sum of the first eight odd numbers, 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15, as every square is.
Nearby numbers
How to read this page
The factor list shows every way 64 splits into equal whole-number groups — 7 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 64 for contexts that do not use decimal.
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