15920
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 37200
- Proper Divisor Sum (Aliquot Sum)
- 21280
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6336
- Möbius Function
- 0
- Radical
- 1990
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 3
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
- 27
- 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
- Multiplicity of highest weight (or singular) vectors associated with character chi_105 of Monster module.at n=45A034493
- Multiplicity of highest weight (or singular) vectors associated with character chi_107 of Monster module.at n=45A034495
- Number of partitions in parts not of the form 11k, 11k+3 or 11k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 4 are greater than 1.at n=43A035946
- Number of integers k not exceeding 2^n such that the cube of number of divisors [A000005(k)] is larger than k.at n=19A056764
- If n mod 2 = 0 then a(n) = n^4/4 - 2*n^2 + 3*n; otherwise, a(n) = n^4/4 - 2*n^2 + 3*n - 5/4.at n=16A064835
- Consider the sequence b(k) such that b(k) and sigma(b(k)) end with the same digit in base 10. Sequence gives values of b(k) such that b(k)/k = 10.at n=39A065255
- a(n) = (35*2^((2*(3*n+2) + 2)/3) - 2*(3*n+2) - 46)/9.at n=5A116971
- Triangle T, read by rows, equal to the matrix square of triangle A117418; also equals a column bisection of triangle A117418: column 2k+1 of T^(1/2) equals column k of T.at n=49A117427
- G.f. satisfies: A(x) = x + 2*x*A(A(x)) - x*A(x)*A(A(A(x))).at n=6A119736
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 0), (1, 1, -1), (1, 1, 0), (1, 1, 1)}.at n=7A150986
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 774", based on the 5-celled von Neumann neighborhood.at n=43A273504
- G.f.: Sum_{n>=0} x^n * (x^n + i)^n / (1 + i*x^(n+1))^(n+1), where i^2 = -1.at n=63A323675
- Number of subsets of {2..n} containing no products of two or more distinct elements.at n=15A326116
- Row sums of the triangular array A357431.at n=39A357417
- Number of subsets of {1..n} containing n such that it is not possible to choose a different binary index of each element.at n=15A370589
- Expansion of 1/((1 - x^4 - x^5)^2 - 4*x^9).at n=35A376725
- E.g.f. satisfies A(x) = ( 1 + (exp(x*A(x)) - 1)/A(x) )^2.at n=6A377339