11221
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 13110
- Proper Divisor Sum (Aliquot Sum)
- 1889
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9576
- Möbius Function
- 0
- Radical
- 1603
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
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
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 86
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Squares written in base 4.at n=19A001739
- Fibonacci numbers written in base 6.at n=17A004689
- Numbers that contain only 1's and 2's. Nonempty binary strings of length n in lexicographic order.at n=36A007931
- Pseudoprimes to base 18.at n=43A020146
- Replacing digits d in decimal expansion of n with d^3 yields a square.at n=12A048391
- Multiples of 7 whose sum of digits is equal to 7.at n=23A063416
- A064637 converted to factorial base.at n=11A064477
- Centered 20-gonal (or icosagonal) numbers.at n=33A069133
- Factorial expansion of A071156.at n=25A071158
- Integers whose decimal expansion start with 1, do not contain zeros and each successive digit to the right is at most one greater than the previous digit.at n=29A071159
- Smallest integer composed of digits 1..n such that no subsequence is repeated and every possible subsequence of length 2 appears.at n=1A075854
- Array in which the n-th row contains the multiples of n using nonzero digits and having a digit sum of n. Sequence contains the rows and a zero entry for rows with no terms (e.g. 10).at n=26A077755
- Index of primorial(n) in A090958.at n=7A090959
- a(n) = Sum_{k=0..n} binomial(floor((n+1)/2), floor((k+1)/2)) * 10^k.at n=4A097177
- Numbers with digits 1 and 2 and at least one of each.at n=27A111066
- Let f(n) be the number of sequences of 1's and 2's which sum to n. Sequence contains the string of sequences.at n=38A114034
- Maximal number of regions obtained by a straight line drawing of the complete bipartite graph K_{n,n}.at n=14A117717
- Zero-free numbers with digit sum equal to 7.at n=46A119461
- Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} such that the set {|p(i)-i|, i=1,2,...,n} has exactly k elements (1<=k<=n).at n=31A125183
- Numbers n with property that for each single digit d of the base 3 expansion of n, we can also see the base 3 expansion of d^2 as a substring. Also n may not contain any 0 digits.at n=19A135464