13728
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
- 48
- Divisor Sum
- 42336
- Proper Divisor Sum (Aliquot Sum)
- 28608
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3840
- Möbius Function
- 0
- Radical
- 858
- Omega Function (Ω)
- 8
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 107
- 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) = floor( n*(n-1)*(n-2)/20 ).at n=66A011902
- a(n) = (n+1)*binomial(n+6,6).at n=7A027818
- Expansion of (theta_3(z)*theta_3(11z) + theta_2(z)*theta_2(11z))^4.at n=19A028612
- Intermediate edge b of smallest (measured by the longest edge) primitive Euler bricks (a, b, c, sqrt(a^2 + b^2), sqrt(b^2 + c^2), sqrt(a^2 + c^2) are integers).at n=37A031174
- a(n) = Sum_{j=0..n} A047072(j, n-j).at n=16A047073
- (Terms in A029661)/2.at n=32A051430
- (Terms in A029647)/2.at n=37A051471
- Number of singular points on n-th order Chmutov surface.at n=32A057870
- Numbers k such that sigma(x) = k has exactly 10 solutions.at n=21A060666
- Coefficient triangle of certain polynomials N(5; m,x).at n=43A062190
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,9.at n=17A064241
- Variance of time for a random walk starting at 0 to reach one of the boundaries at +n or -n for the first time.at n=12A072819
- Expansion of (1-x)/(1+2*x+x^2-x^3).at n=27A078064
- Smallest multiple of n beginning with the n-th prime.at n=32A078208
- Consider all compositions (ordered partitions) of n into n parts, allowing zeros. E.g., for n = 3 we get 300, 030, 003, 210, 120, 201, 102, 021, 012, 111. Then a(n) is the total number of 1's.at n=7A097070
- Structured hexagonal diamond numbers (vertex structure 5).at n=21A100178
- a(n) = binomial(n+7,7)*binomial(n+12,7).at n=1A104680
- T(n,k) = 2^k*binomial(n,2k+1), where 0 <= k <= floor((n-1)/2), n >= 1.at n=45A105070
- A number triangle related to the central binomial coefficients.at n=47A112336
- Triangle read by rows: T(n,k) is the number of Grand Dyck paths of semilength n having first return to the x-axis at (2k,0) (n,k >= 1). (A Grand Dyck path of semilength n is a path in the half-plane x >= 0, starting at (0,0), ending at (2n,0) and consisting of steps u=(1,1) and d=(1,-1)).at n=47A118921