15444
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
- 48
- Divisor Sum
- 47040
- Proper Divisor Sum (Aliquot Sum)
- 31596
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 858
- Omega Function (Ω)
- 7
- 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
- 27
- 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 in S_n with a certain property.at n=15A013498
- Triangle read by rows: T(n,k) = number of 2 X inf arrays [ n, n1, n2, ...; k, k1, k2,... ] with n>=n1>n2>...>=0, k>=k1>k2...>=0, n>k, n1>k1, ...; n >= 1, k >= 0. Note that once ni or ki = 0, the strict inequalities become equalities (constant 0 thereafter).at n=49A039597
- Numbers k such that k*2^k - (k-1) is prime.at n=20A046847
- Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= n/2.at n=24A047170
- Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= (n-1)/2.at n=24A047181
- (Terms in A029665)/2.at n=42A051425
- (Terms in A029643)/2.at n=37A051469
- a(n) = C(n)*(5*n+1) where C(n) = Catalan numbers (A000108).at n=7A051945
- Partial sums of A050483.at n=7A052181
- Partial sums of A050404.at n=7A052226
- Degrees of irreducible representations of alternating group A_14.at n=42A060717
- a(n) = 3*n*(4*n-1).at n=36A062783
- A unitary phi reciprocal amicable number: consider two different numbers r, s which satisfy the following equation for some integer k: uphi(r) = uphi(s) = (1/k) * r * s / (r-s); or equivalently, 1/uphi(r) = 1/uphi(s) = k * (1/s - 1/r); sequence gives r numbers.at n=13A080766
- Sequence arising from enumeration of domino tilings of Aztec Pillow-like regions.at n=6A092443
- Eighth column (m=7) of (1,4)-Pascal triangle A095666.at n=8A095670
- Triangle read by rows, T(n,k) = C(n,k)*C(2*k,k)/(k+1), n >= 0, 0 <= k <= n.at n=52A098474
- Number of permutations of n distinct letters (ABCD...) each of which appears thrice with n-3 fixed points.at n=12A124007
- Triangle read by rows. T(n, k) = binomial(n, k) * CatalanNumber(n - k).at n=47A124644
- G.f. satisfies: A(x) = Series_Reversion( x/(1 + A(x) + A(x)^2) ).at n=7A140097
- Number of planar triangular n X n X n nonnegative integer grids with mirror symmetry about one altitude with every similarly oriented 5 X 5 X 5 subtriangle summing to 14.at n=0A154091