15615
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
- 12
- Divisor Sum
- 27144
- Proper Divisor Sum (Aliquot Sum)
- 11529
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8304
- Möbius Function
- 0
- Radical
- 5205
- Omega Function (Ω)
- 4
- 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
- 84
- 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
- no
- Odd
- yes
Appears in sequences
- Triangle of coefficients of generating function of 4-ary rooted trees of height at most n.at n=53A036606
- Number of 4-ary rooted trees with n nodes and height at most 4.at n=22A036609
- Number of 4-ary rooted trees with n nodes and height exactly 4.at n=22A036628
- a(n) = (3*n*F(2n-1) + (3-n)*F(2n))/5 where F() = Fibonacci numbers A000045.at n=10A059502
- The array in A059502 read by antidiagonals in 'up' direction.at n=54A059503
- A sequence of asymptotic density zeta(9) - 1, where zeta is the Riemann zeta function.at n=31A143035
- Numbers of length n binary words with fewer than 6 0-digits between any pair of consecutive 1-digits.at n=14A145114
- a(1)=0, a(n) = n^3 - a(n-1).at n=30A153026
- a(n) = 625*n^2 - 2*n.at n=4A158373
- Antidiagonal sums of A163280.at n=28A163983
- Monotonic ordering of nonnegative differences 5^i-10^j, for 40>= i>=0, j>=0.at n=17A192201
- Number of 0..4 arrays of length n avoiding the consecutive pattern 0..4.at n=5A206451
- T(n,k) = number of 0..k arrays of length n avoiding the consecutive pattern 0..k.at n=41A206455
- Number of 0..n arrays of length n+2 avoiding the consecutive pattern 0..n.at n=3A206456
- Number of n X 4 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 n X 4 array.at n=12A219350
- Triangle T(n, k) = Numbers of ways to place k points on a triangular grid of side n so that no three of them are vertices of an equilateral triangle of any orientation. Triangle read by rows.at n=32A240439
- Triangle of coefficients of Gaussian polynomials [2n+7,6]_q represented as finite sum of terms (1+q^2)^k*q^(g-k), where k = 0,1,...,g with g=6n+3.at n=59A267486
- Number of length-n 0..7 arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order.at n=8A268955
- Decimal representation of the diagonal from the origin to the corner of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 57", based on the 5-celled von Neumann neighborhood.at n=15A285607
- a(n) = Sum_{k=0..n} 2^k * binomial(n+2,k+2) * binomial(2*k+4,k+4).at n=4A387307