11756
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 20580
- Proper Divisor Sum (Aliquot Sum)
- 8824
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5876
- Möbius Function
- 0
- Radical
- 5878
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 81
- 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
- yes
- Odd
- no
Appears in sequences
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 1 (mod 5).at n=49A035562
- a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A048149.at n=34A049714
- Iccanobirt prime indices (15 of 15): Indices of prime numbers in A102125.at n=19A102145
- Riordan array ((1-x^2)/(1+3x+x^2),x/(1+3x+x^2)).at n=38A110168
- Triangle read by rows: characteristic polynomials of certain matrices, see Mathematica program.at n=38A124040
- 3-comma numbers: n occurs in the sequence S[k+1]=S[k]+10*last_digit(S[k-1])+first_digit(S[k]) for three different splittings n=concat(S[0],S[1]).at n=6A166513
- T(n,k)=Number of arrays of n 0..k integers with no sum of consecutive elements equal to a disjoint adjacent sum of an equal number of elements.at n=50A215190
- Number of arrays of 6 0..n integers with no sum of consecutive elements equal to a disjoint adjacent sum of an equal number of elements.at n=4A215193
- Number of cyclotomic cosets of 9 mod 10^n.at n=27A220020
- Coordination sequence for (2,3,9) tiling of hyperbolic plane.at n=34A265059
- Numbers k such that k!6 - 27 is prime, where k!6 is the sextuple factorial number (A085158).at n=23A289698
- a(n) is the least k such that A295520(k) = n.at n=41A295793
- a(n) is the cardinality of S(n), the subset of partitions of n such that there are enough smaller parts to add together to be greater than a larger part.at n=33A338085
- Number of integer partitions of n of whose permutations do not all have distinct runs.at n=34A351203
- Numbers k such that 1 is in the transitive closure of the map x -> A353313(x) when starting iterating from x=k.at n=44A353306
- Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 2 + 3*x, p(n,x) = u*p(n-1,x) + v*p(n-2,x) for n >= 3, where u = p(2,x), v = 1 - 2*x - x^2.at n=32A367297
- a(n) is the number of permutations of the multiset 1,1, 2,2, ..., n,n such that at least one pair k,k stays at its initial locations 2k-1, 2k.at n=4A375223