Number reference
1 explained.
1: one, neither prime nor composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- one
- Classification
- neither prime nor composite
- Factors
- 1
- Prime factorization
- 1
- Square root
- 1
- Cube root
- 1
- Binary
- 1
- Octal
- 1
- Hexadecimal
- 1
- Roman numeral
- I
- Digit sum
- 1
- Digital root
- 1
1 in everyday use
One is the multiplicative identity: multiplying or dividing by it leaves a number unchanged. It is deliberately excluded from the primes, because allowing it would break the rule that every number has one unique prime factorisation.
Nearby numbers
How to read this page
One sits outside the prime and composite split. It divides every integer, its only divisor is itself, and raising it to any power leaves it unchanged, so factorisation rules treat it as a special case.
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