15228
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 30
- Divisor Sum
- 40656
- Proper Divisor Sum (Aliquot Sum)
- 25428
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4968
- Möbius Function
- 0
- Radical
- 282
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 133
- 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) = 9*(n-2)^2 * (n^2 - 2*n - 1).at n=6A060788
- When cubed gives number composed just of the digits 1, 2, 3, 4, 5.at n=20A061813
- Inverse of Riordan array (1/(1-x)^2,x(1-x)/(1+x)), A104698.at n=38A110271
- McKay-Thompson series of class 40B for the Monster group.at n=49A112179
- Coefficient of x^2 in the polynomial (x-p(n))*(x-p(n+1))*(x-p(n+2))*(x-p(n+3)), where p(k) is the k-th prime.at n=13A127348
- 3 times 10-gonal (or decagonal) numbers: a(n) = 3*n*(4*n-3).at n=36A152767
- a(n) = (2*n^3 + 5*n^2 - 3*n)/2.at n=23A162256
- Number of symmetry classes of 3 X 3 semimagic squares with distinct positive values < n.at n=17A173723
- Number of numerical semigroups of multiplicity n and genus n+2.at n=45A180739
- Number of connected components in all simple labeled graphs with n nodes having degrees at most one.at n=8A189940
- Number of subsets of {1,...,n} containing two elements whose difference is 2.at n=14A209398
- Phi(n) values in A115921.at n=29A216381
- a(n) = -3*n^2*(n-1)^4*(n+1)*(11*n^3+49*n^2-439*n+171).at n=2A259395
- Number of nX4 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.at n=3A283722
- T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.at n=24A283726
- Number of 4Xn 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.at n=3A283729
- Expansion of Product_{n>=1} ((1 + (8*x)^n)/(1 - (8*x)^n))^(1/8).at n=5A303381
- -1 + Product_{n>=1} 1/(1 + a(n)*x^n) = g.f. of A000040 (prime numbers).at n=17A305882
- Number of permutations of [n] where the length of the longest increasing subsequence is larger than the length of the longest decreasing subsequence.at n=7A321314
- Fully multiplicative with a(prime(k)) = Lucas(2*(k+1)) for k-th prime p, where Lucas(n) = A000032(n).at n=44A324900