15886
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 26352
- Proper Divisor Sum (Aliquot Sum)
- 10466
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7176
- Möbius Function
- 0
- Radical
- 1222
- Omega Function (Ω)
- 4
- 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
- 146
- 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
- Numbers of Twopins positions.at n=18A005683
- a(0) = 1, a(n) = 11*n^2 + 2 for n>0.at n=38A010003
- Numbers k such that (k, sigma(k)) lies on a circle with integral radius centered at the origin, i.e., k^2 + sigma(k)^2 is a square.at n=24A066764
- Number of incongruent ways to tile a 5 X 2n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point.at n=39A068930
- Numbers n such that 2*10^n + 5*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=6A102956
- a(n) = 8*n^2 - 7*n + 1.at n=45A125201
- Arises in classification of base sequences.at n=22A173061
- a(n) = 94*n^2.at n=13A174337
- Riordan array (((1+x)/(1-x-x^2))^m, x*A000108(x)), m=3.at n=59A185678
- Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 246", based on the 5-celled von Neumann neighborhood.at n=13A280331
- Number of partitions of n into parts of exactly four sorts which are introduced in ascending order such that sorts of adjacent parts are different.at n=7A320546
- G.f.: Sum_{k>=0} x^(2^k) / Product_{j=1..2^k} (1 - x^j).at n=47A339447
- Nonsquarefree numbers k such that A003415(k) divides A276086(k), where A003415 is the arithmetic derivative, and A276086 is the primorial base exp-function.at n=29A371085
- G.f. A(x) satisfies A(x) = ( 1 + 4*x*A(x)/(1 - x) )^(1/2).at n=19A372035
- Numbers k such that sigma(k) = psi(k) + tau(k)^2.at n=24A390296
- a(n) = Sum_{k=0..floor(n/6)} (-1)^k * (7*k+1) * binomial(2*n-5*k+1,n-6*k)/(2*n-5*k+1).at n=10A390477