11
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 2
- Digital Root
- 2
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 12
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10
- Möbius Function
- -1
- Radical
- 11
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- yes
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 14
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- yes
- Safe Prime
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 5
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Names
- German
- elf· ordinal: elfte
- English
- eleven· ordinal: eleventh
- Spanish
- once· ordinal: undécimo
- French
- onze· ordinal: onzième
- Italian
- undici· ordinal: 11º
- Latin
- undecim· ordinal: 11.
- Portuguese
- onze· ordinal: 11º
Appears in sequences
- Integer part of square root of n-th prime.at n=30A000006
- Integer part of square root of n-th prime.at n=31A000006
- Integer part of square root of n-th prime.at n=32A000006
- Integer part of square root of n-th prime.at n=33A000006
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=10A000008
- Smallest prime power >= n.at n=9A000015
- Smallest prime power >= n.at n=10A000015
- Number of primitive permutation groups of degree n.at n=8A000019
- Number of primitive permutation groups of degree n.at n=36A000019
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=10A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=10A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=6A000028
- Numbers that are not squares (or, the nonsquares).at n=7A000037
- a(n) is the number of partitions of n (the partition numbers).at n=6A000041
- Unary representation of natural numbers.at n=1A000042
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=21A000052
- Number of trees with n unlabeled nodes.at n=7A000055
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=7A000062
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=5A000069
- Number of simple graphs on n unlabeled nodes.at n=4A000088