12936
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 41040
- Proper Divisor Sum (Aliquot Sum)
- 28104
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3360
- Möbius Function
- 0
- Radical
- 462
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 4
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
- 50
- 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
- arctan(arctan(x)*sin(x))=2/2!*x^2-12/4!*x^4-50/6!*x^6+12936/8!*x^8...at n=4A012423
- tanh(arctan(x)*sin(x))=2/2!*x^2-12/4!*x^4-50/6!*x^6+12936/8!*x^8...at n=3A012427
- Even octagonal numbers: a(n) = 4*n*(3*n-1).at n=33A014642
- a(n) = (1/3)*(n^2 + 2*n + 3)*(n+1)^2.at n=13A014820
- a(n) = (prime(n+2)^2 - 1)/3.at n=42A024700
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 7 (most significant digit on left).at n=49A029452
- Triangle read by rows: T(k,j) = ((2*j+1)/(k+1))*binomial(2*j,j)*binomial(2*k-2*j,k-j).at n=48A033820
- Positions of 4-digit terms in the continued fraction for Pi (3 is at position 0).at n=13A048959
- Expansion of generating function A_{UU}^(2)(4n;2,1,1).at n=3A059488
- Numbers k such that sigma(x) = k has exactly 10 solutions.at n=20A060666
- Triangle read by rows: T(n, k) = [z^k] P(n, z) where P(n, z) = Sum_{k=0..n} binomial(n, k) * Pochhammer(n - k + c, k) * z^k / k! and c = 4.at n=42A062145
- a(n) = 7*n^2 + 14*n.at n=41A067727
- Numbers n such that n*phi(n-1) is a perfect square.at n=17A069069
- a(n) = 140*C(2n,n)/(n+4).at n=6A078819
- Generalized centered polygonal numbers.at n=14A081282
- An interleaved sequence of pyramidal and polygonal numbers.at n=27A081284
- Row sums in A083167.at n=21A083170
- A sequence derived from pentagonal numbers, or a Stirling number of the first kind matrix.at n=15A094952
- Coordination sequence for octagonal tiling is a(n)*sqrt(2) + A103909(n).at n=33A103908
- a(n) = binomial(n+6,6)*binomial(n+9,6).at n=2A105942