Number reference
26 explained.
26: twenty-six, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- twenty-six
- Classification
- composite
- Factors
- 1, 2, 13, 26
- Prime factorization
- 2 × 13
- Square root
- 5.09902
- Cube root
- 2.962496
- Binary
- 11010
- Octal
- 32
- Hexadecimal
- 1A
- Roman numeral
- XXVI
- Digit sum
- 8
- Digital root
- 8
What makes 26 notable
- Semiprime. 26 = 2 × 13, a product of exactly two primes. That gives it just four divisors, so it splits into equal groups in only two non-trivial ways.
26 in everyday use
Twenty-six letters make up the English alphabet, and 26 is the atomic number of iron, the most common element on Earth by mass. A marathon is 26 miles and 385 yards, a distance fixed at the 1908 London Olympics and made standard in 1921. A standard deck holds 26 red cards and 26 black ones. The human foot has 26 bones, and Switzerland is made up of 26 cantons.
Twenty-six is the only number that sits directly between a perfect square, 25, and a perfect cube, 27. Fermat claimed this in the 1600s and it was later proved rigorously. It factors as 2 × 13, making it a semiprime, and it is the number of sporadic simple groups in the classification of finite simple groups. In hexadecimal it is written 1A.
Nearby numbers
How to read this page
The factor list shows every way 26 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 26 for contexts that do not use decimal.
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