15660
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
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 50400
- Proper Divisor Sum (Aliquot Sum)
- 34740
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4032
- Möbius Function
- 0
- Radical
- 870
- 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
- 102
- 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
- Expansion of Product_{k>=1} (1-x^k)^30.at n=4A010835
- Write 1, 2, 3, 4, ... counterclockwise in a hexagonal spiral around 0 starting left down, then a(n) is the sequence found by reading from 0 in the vertical upward direction.at n=36A063436
- Let f(x)=(largest digit of x)^(smallest digit of x) + x (A097385). Sequence gives numbers n such that f(n) and f(n+1) are both prime.at n=35A097387
- Triangle T(n,k), 0 <= k <= n, read by rows defined by: T(0,0)=1, T(n,k)=0 if k < 0 or if k > n, T(n,0) = 4*T(n-1,0) + T(n-1,1), T(n,k) = T(n-1,k-1) + 5*T(n-1,k) + T(n-1,k+1) for k >= 1.at n=22A126331
- a(n) = binomial(n+1,2)*6^2.at n=29A162940
- Difference A063990(2n)-A063990(2n-1) between amicable numbers.at n=15A178542
- Number of 2-step one or two space at a time rook's tours on an n X n board summed over all starting positions.at n=44A187287
- n - (sum of prime factors of n^2+1) is a positive square.at n=41A216896
- Triangle read by rows: coefficients of second-order hypergeometric-harmonic polynomials.at n=26A222061
- Product of the sum of the divisors of n and the sum of the divisors of n-th prime.at n=39A272173
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 771", based on the 5-celled von Neumann neighborhood.at n=23A273500
- Number of skew partitions whose quotient diagram is connected and whose numerator has weight n.at n=17A300120
- Expansion of 1/(2 - Sum_{k>=0} k!*x^k/(1 + x)^(k+1)).at n=8A302557
- First differences of A063990 (amicable numbers arranged in increasing order).at n=30A306613
- Number of odd parts in the partitions of n into 9 parts.at n=39A309656
- a(n) = (1/24)*n*(n - 1)*(n - 3)*(n - 14).at n=30A319930
- Exponential (2,4)-perfect numbers: numbers m such that esigma(esigma(m)) = 4m, where esigma(m) is the sum of exponential divisors of m (A051377).at n=7A328133
- Expansion of g.f. A(x) satisfying 1 = Sum_{n=-oo..+oo} x^n * (2*A(x) - (-x)^n)^(3*n-1).at n=4A361773
- Number of binary strings of length n in which the number of substrings 00 is one more than that of substrings 01.at n=17A370048
- a(n) is the smallest integer k such that the Diophantine equation x^3 + y^3 + z^3 = k^3, where 0 < x <= y <= z has exactly n integer solutions.at n=46A377444