15081
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 21984
- Proper Divisor Sum (Aliquot Sum)
- 6903
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9120
- Möbius Function
- -1
- Radical
- 15081
- Omega Function (Ω)
- 3
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 89
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- E.g.f. satisfies A'(x) = A(x/(1-x)).at n=7A001063
- a(n) = Sum_{k=n+1..2*n} T(n,k), T given by A027052.at n=9A027077
- Odd 9-gonal (or enneagonal) numbers.at n=33A028991
- Enneagonal numbers for which the product of the digits is also an enneagonal number.at n=20A117052
- Number of line perfect perfect graphs on n nodes.at n=9A123432
- Position of cubes in the EKG sequence (A064413).at n=24A140418
- Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.at n=10A146066
- Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.at n=22A146068
- Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.at n=23A146068
- Number of binary strings of length n with equal numbers of 0001 and 0010 substrings.at n=15A164155
- Number of (n+4) X 10 0..1 matrices with each 5 X 5 subblock idempotent.at n=12A224688
- Numbers n such that n^8+8 and n^8-8 are prime.at n=18A239503
- Number of minimal overlapping permutations starting with 2 of length n.at n=7A260159
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 286", based on the 5-celled von Neumann neighborhood.at n=34A271123
- Expansion of 1/((1-x)^4 - 8*x^4)^(1/4).at n=13A376835
- Position of start of first run of alternating bit values in the base-2 representation of Pi, or -1 if no such run exists.at n=14A382307