Number reference
63 explained.
63: sixty-three, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- sixty-three
- Classification
- composite
- Factors
- 1, 3, 7, 9, 21, 63
- Prime factorization
- 3 × 3 × 7
- Square root
- 7.937254
- Cube root
- 3.979057
- Binary
- 111111
- Octal
- 77
- Hexadecimal
- 3F
- Roman numeral
- LXIII
- Digit sum
- 9
- Digital root
- 9
What makes 63 notable
- Factor structure. 63 breaks down into 2 distinct primes (3, 7) and has 6 divisors in total, so it can be split into equal whole-number groups 4 ways beyond 1 and itself.
63 in everyday use
Sixty-three is the atomic number of europium, the element whose red glow lit the phosphors of colour television tubes and now authenticates euro banknotes under ultraviolet light. A mule has 63 chromosomes, the average of its horse parent's 64 and donkey parent's 62, which is why mules are almost always sterile. US Route 63 runs from northern Wisconsin down to Louisiana, and +63 is the international dialling code for the Philippines.
Sixty-three is 2⁶ − 1, so in binary it is 111111, six ones in a row, and it is the largest value that fits in six bits. It is the sum of the first six powers of two, 1 + 2 + 4 + 8 + 16 + 32. It factors as 7 × 9, or 3² × 7, and it is a Woodall number, 4 × 2⁴ − 1. Unlike 31 and 127 it is not prime, showing that 2ⁿ − 1 is prime only for some exponents.
Nearby numbers
How to read this page
The factor list shows every way 63 splits into equal whole-number groups — 6 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 63 for contexts that do not use decimal.
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