13872
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
- 4
Divisibility
- Divisor Count
- 30
- Divisor Sum
- 38068
- Proper Divisor Sum (Aliquot Sum)
- 24196
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4352
- Möbius Function
- 0
- Radical
- 102
- Omega Function (Ω)
- 7
- 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
- 32
- 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
- a(n) = n^2*(n^2 - 1)/6.at n=17A008911
- 4th Fibonacci polynomial evaluated at x=n!.at n=4A020550
- Number of (undirected) Hamiltonian paths in n-Moebius ladder.at n=24A020875
- Number of nonisomorphic commutative groupoids with no idempotents.at n=4A030260
- "BFK" (reversible, size, unlabeled) transform of 2,1,1,1...at n=27A032044
- a(1) = 1, a(2) = 16, a(n) = lcm(48, 2n^2) for n>2.at n=33A032444
- a(1) = 1, a(2) = 16, a(n) = lcm(48, 2n^2) for n>2.at n=16A032444
- Triangle read by rows: T(n,k) is the number of commutative groupoids with n elements and k idempotents.at n=10A038021
- Denominators of continued fraction convergents to sqrt(145).at n=3A041265
- a(n) = Sum_{d|3} phi(d)*n^(3/d).at n=24A054602
- Number of rods required to make a 3-D cube of side length n.at n=16A059986
- a(n) = n^2*(2*n^2 + 1)/3.at n=12A071270
- Numbers n such that sopf(n) = sopf(n-1) - sopf(n-2), where sopf(x) = sum of the distinct prime factors of x.at n=5A076527
- G.f.: Product_{n >= 0} (1+x^(2n+1))/(1-x^(2n+1)).at n=39A080054
- a(n) = A004061(n) - 1.at n=13A086123
- Expansion of g.f. Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 7.at n=26A091778
- Structured rhombic triacontahedral numbers (vertex structure 7).at n=11A100165
- a(n) = (19*5^n - 16*3^n + 1) / 4.at n=5A102105
- Triangle read by rows: T(n,k) is the number of hill-free Schroeder paths of length 2n that have k returns to the x-axis (0<=k<=floor(n/2)). A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1.at n=21A114692
- a(n) = 12*n^2.at n=34A135453