26 (twenty-six) is the natural number following 25 and preceding 27.

Cardinal	twenty-six
Ordinal	twenty-sixth
Factorization
Roman numeral	XXVI
Binary	11010
Hexadecimal	1A

In mathematics

Twenty-six is a composite number, its proper divisors being 1, 2, and 13. 26 is the only number between a square number and a cube number, the numbers being 25 (5 squared) and 27 (3 cubed).

There is no solution to the equation φ(x) = 26, making 26 a nontotient. Nor is there a solution to x - φ(x) = 26, making 26 a noncototient.

In the classification of finite simple groups there are 26 sporadic groups.

In science

• The atomic number of iron

In astronomy,

Messier object M26, a magnitude 9.5 open cluster in the constellation Scutum

The New General Catalogue object NGC 26 , a spiral galaxy in the constellation Pegasus

The Saros number of the solar eclipse series which began on -2022 March 29 and ended on -724 May 17. The duration of Saros series 26 was 1298.1 years, and it contained 73 solar eclipses.

The Saros number of the lunar eclipse series which began on -1937 August 28 and ended on -386 March 17. The duration of Saros series 26 was 1550.5 years, and it contained 87 lunar eclipses.

In other fields

Twenty-six is:

• The number of letters in the English alphabet, if majuscules are not distinguished from minuscules.
• The designation of Interstate 26, a freeway that runs from South Carolina to North Carolina.
• The number of spacetime dimensions in bosonic string theory.
• Often the number of episodes in a Japanese anime series. For example, Cowboy Bebop, Outlaw Star and Trigun.
• Historical years: 26 A.D., 26 B.C., or 1926