15860
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 36456
- Proper Divisor Sum (Aliquot Sum)
- 20596
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5760
- Möbius Function
- 0
- Radical
- 7930
- Omega Function (Ω)
- 5
- 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
- yes
- 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
- Fibonacci sequence beginning 0, 26.at n=15A022360
- Susceptibility series H_3 for 2-dimensional Ising model (divided by 2).at n=15A054410
- a(n) = Sum_{k=1..n} d(k)*prime(k), where d(k) = A001223.at n=40A064009
- Non-palindromic numbers n such that phi(n) = phi(reversal(n)).at n=16A097647
- The number of permutations p of {1,...,n} such that |p(i)-p(i+1)| is in {1,2,3,4} for all i from 1 to n-1.at n=8A174701
- Number of permutations p of {1,...,n} such that |p(i+1)-p(i)| < k, k=2,...,n; T(n,k), read by rows.at n=31A249631
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 189", based on the 5-celled von Neumann neighborhood.at n=28A270679
- Numbers m such that the numerator of Sum_{k=1..m, gcd(k,m) = 1} 1/k is divisible by m^3.at n=39A290815
- Number of maximal cliques in the n-polygon diagonal intersection graph.at n=23A291949
- Practical numbers z such that z^2 = x^2 + y^2 for some practical numbers x and y with gcd(x,y,z) = 4.at n=26A294112
- a(n) = n*((4*n + 1)*(7*n - 4) + 15*n*(-1)^n)/48.at n=29A302766
- Numbers m such that the numerator of Sum_{k=1..m, gcd(k,m) = 1} 1/k^2 is divisible by m^2.at n=51A309696
- Triangle read by rows: T(n,k) is the number of self-avoiding paths of length n-1+2*k from NW to SW corners in the n X n grid graph (0 <= k <= A000217(n-1), n >= 1).at n=31A329633
- Total number of weak left-to-right maxima in Dyck paths of semilength n.at n=9A346158
- Square array A(n,k) = A388991(A388981(n, k)), read by descending antidiagonals.at n=49A388989