12840
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
- 32
- Divisor Sum
- 38880
- Proper Divisor Sum (Aliquot Sum)
- 26040
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3392
- Möbius Function
- 0
- Radical
- 3210
- Omega Function (Ω)
- 6
- 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
- 24
- 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
- Number of permutations of [n] with no 3-term arithmetic progression.at n=13A003407
- [ (4th elementary symmetric function of S(n))/(2nd elementary symmetric function of S(n)) ], where S(n) = {first n+3 positive integers congruent to 1 mod 4}.at n=12A024389
- Triangle of coefficients of Gandhi polynomials.at n=17A036970
- a(n) = (n-1)! * Sum_{k=1..n} floor(k^k/k!).at n=5A054202
- Least k such that k*n^n +/- 1 are twin primes.at n=36A076810
- Another version of triangular array in A036970: triangle T(n,k), 0<=k<=n, read by rows; given by [0, 1, 2, 4, 6, 9, 12, 16, 20, 25, 30, ...] DELTA [1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, ...] where DELTA is the operator defined in A084938.at n=24A094346
- Series expansion for mean-squared radius of gyration of stack polygons on square lattice.at n=5A121780
- Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=10.at n=18A135195
- Values of y in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z arranged in order of increasing x.at n=19A138668
- a(n) = n*(8*n+1).at n=40A139275
- G.f.: A(x) = Sum_{n>=0} log(1 + x/(1-2^n*x))^n/n!.at n=7A159602
- Record gaps between nonprime prime powers.at n=25A167186
- Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal or vertical neighbor.at n=3A182192
- Triangle read by rows: T(n,k) is the number of permutations of [n] having k adjacent cycles (0 <= k <= n). An adjacent cycle is a cycle of the form (i, i+1, i+2, ...) (including 1-element cycles).at n=36A184184
- Number of permutations of {1,2,...,n} having no cycles of the form (i, i+1, i+2, ..., i+j-1) (j >= 1).at n=8A184185
- Number of n X 5 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).at n=2A208299
- T(n,k)=Number of n X k nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).at n=16A208301
- Number of 2Xn nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).at n=4A208302
- Number of (w,x,y,z) with all terms in {1,...,n} and |x-y| = w + |y-z|.at n=30A212683
- Number of diagonal and antidiagonal neighbor colorings of the even squares of an nX5 array with new integer colors introduced in row major order.at n=3A215901