12640
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 30240
- Proper Divisor Sum (Aliquot Sum)
- 17600
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4992
- Möbius Function
- 0
- Radical
- 790
- 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
- 81
- 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) = Sum_{k=0..n} T(k) where T(n) are the tribonacci numbers A000073.at n=16A008937
- Define the generalized Pisot sequence T(a(0),a(1)) by: a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n). This is T(4,8).at n=13A018921
- Expansion of (theta_3(z)*theta_3(5z)+theta_2(z)*theta_2(5z))^4.at n=27A028589
- Theta series of odd 8-dimensional 5-modular lattice O(5).at n=27A029719
- Number of possible queen moves on an n X n chessboard.at n=15A035005
- Numbers n such that n | sigma_13(n).at n=24A055717
- Duplicate of A008937.at n=16A073769
- 4 times hexagonal numbers: a(n) = 4*n*(2*n-1).at n=40A085250
- Average of 4 primes where the integer Schwarzian derivative is zero.at n=15A094903
- Let f(x)=(largest digit of x)^(smallest digit of x) + x (A097385). Sequence gives numbers n such that f(n) and f(n+1) are both prime.at n=29A097387
- Triangle read by rows: T(n,k) is the number of binary sequences of length n containing k subsequences 0011 (n,k>=0).at n=36A118884
- Numbers n such that n^24 + 1 = p*q with p,q distinct primes.at n=22A119982
- List of different composites in Pascal-like triangles with index of asymmetry y = 2 and index of obliquity z = 0 or z = 1.at n=34A141066
- a(n) = prime(prime(prime(A028815(n) - 1) - 1) - 1) - 1.at n=16A141133
- a(n) = 2*n^3 - 3*n^2 + 5.at n=19A152064
- a(n) = n*n in the arithmetic where digits are multiplied in base 10 (as usual) but when digits are to be added they are also multiplied in base 10.at n=32A169920
- G.f.: exp( Sum_{n>=1} Sum_{k>=1} sigma(n)^k * x^(n*k) / n ).at n=14A185301
- Number of 3 X n arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 3 X n array.at n=23A219520
- Number of cyclotomic cosets of 9 mod 10^n.at n=28A220020
- Numbers x such that sigma(x)=sigma(V(x)), where sigma(x) is the sum of the divisors of x and V(x) the transform defined in A245252.at n=7A245469