Number reference
93 explained.
93: ninety-three, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- ninety-three
- Classification
- composite
- Factors
- 1, 3, 31, 93
- Prime factorization
- 3 × 31
- Square root
- 9.643651
- Cube root
- 4.530655
- Binary
- 1011101
- Octal
- 135
- Hexadecimal
- 5D
- Roman numeral
- XCIII
- Digit sum
- 12
- Digital root
- 3
What makes 93 notable
- Semiprime. 93 = 3 × 31, a product of exactly two primes. That gives it just four divisors, so it splits into equal groups in only two non-trivial ways.
93 in everyday use
The Earth orbits about 93 million miles from the Sun, the distance astronomers call one astronomical unit. Ninety-three is the atomic number of neptunium, the first element beyond uranium, made in 1940 and named for the next planet out. United Airlines Flight 93 was the aircraft whose passengers fought back on 11 September 2001, crashing in Pennsylvania rather than reaching Washington. Neptunium-237, its longest-lived isotope, has a half-life of about 2.1 million years.
Ninety-three is 3 × 31, both factors leaving a remainder of 3 when divided by 4, which makes it a Blum integer of the kind used in some cryptographic schemes. In binary it is 1011101, a palindrome, and in base 5 it is 333, a repdigit. Its reversal, 39, is also three times a prime. It has four divisors, and its digits sum to 12.
Nearby numbers
How to read this page
The factor list shows every way 93 splits into equal whole-number groups — 4 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 93 for contexts that do not use decimal.
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