11
11 is a prime number, the atomic number of sodium, and the standard number of players on a football (soccer) or cricket team.
- Odd
- Prime
Where 11 fits
Why 11 is special
11's ordinary mathematical profile as a two-digit repdigit prime sits alongside one of the most recognisable team sizes in world sport.
Same number, different meanings
How 11 is understood across different contexts — never implying one meaning because of another.
- Mathematics
11's ordinary mathematical profile as a two-digit repdigit prime sits alongside one of the most recognisable team sizes in world sport.
- Science
11 is the atomic number of sodium.
- Sport
A standard football (soccer) team and a standard cricket team each field 11 players on the pitch at once — one of the most widely recognised team sizes in world sport.
11 is part of
Factors & digit properties
- Divisors (2)
- 1, 11
- Prime factorisation
- 11
- Digit sum
- 2
- Digital root
- 2
Representations
- Decimal
- 11
- Binary
- 1011
- Octal
- 13
- Hexadecimal
- b
- Roman numeral
- XI
- Scientific notation
- 1.100 × 10^1
Other mathematical patterns
- Palindromic number
- Deficient number
- Repdigit
- Lucas number
- Sophie Germain prime
- Safe prime
- Twin prime
Related numbers & connections
11 is a factor of 99 (11 × 9 = 99).
View 99 →Science
11 is the atomic number of sodium.
DocumentedScience
Sport
A standard football (soccer) team and a standard cricket team each field 11 players on the pitch at once — one of the most widely recognised team sizes in world sport.
DocumentedSport
Common questions
Is 11 a prime number?
Yes, 11 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 11?
The factors of 11 are 1, 11.
What is 11 in Roman numerals?
11 in Roman numerals is XI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026