Number reference
68 explained.
68: sixty-eight, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- sixty-eight
- Classification
- composite
- Factors
- 1, 2, 4, 17, 34, 68
- Prime factorization
- 2 × 2 × 17
- Square root
- 8.246211
- Cube root
- 4.081655
- Binary
- 1000100
- Octal
- 104
- Hexadecimal
- 44
- Roman numeral
- LXVIII
- Digit sum
- 14
- Digital root
- 5
What makes 68 notable
- Factor structure. 68 breaks down into 2 distinct primes (2, 17) and has 6 divisors in total, so it can be split into equal whole-number groups 4 ways beyond 1 and itself.
68 in everyday use
Sixty-eight is the atomic number of erbium, whose pink salts colour glass and whose fibre-optic amplifiers carry much of the world's internet traffic. The year 1968 was one of upheaval — assassinations, protests, and the Prague Spring — and Elvis Presley's televised comeback that December is known simply as the '68 Comeback Special. In Latin America, 68 often evokes the Tlatelolco protests in Mexico City.
Sixty-eight is 2² × 17 and the sum of two squares, 64 + 4. It can be written as the sum of two primes in exactly two ways, 7 + 61 and 31 + 37, and it is the largest known even number with that property; every larger even number tested has more. Sixty-eight is also a happy number: 36 + 64 = 100, and then 1. In binary it is 1000100.
Nearby numbers
How to read this page
The factor list shows every way 68 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 68 for contexts that do not use decimal.
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