15745
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19584
- Proper Divisor Sum (Aliquot Sum)
- 3839
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12144
- Möbius Function
- -1
- Radical
- 15745
- Omega Function (Ω)
- 3
- 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
- 115
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- Numerator of Sum_{p prime, p-1|n} 1/p.at n=29A027759
- Numerator of sum_{p prime, p-1 divides 2*n} 1/p.at n=14A027761
- Maximal number of spanning paths in a tournament on n nodes.at n=9A038375
- G.f.: (x+4*x^3+x^5)/((1-x)^2*(1-x^2)^2*(1-x^3)).at n=28A083707
- Numbers n such that more than half of the reduced-residue system modulo 210 consists of primes in the following sense: in {210n + R} more than 24 = phi(210)/2 primes occur, i.e., 25-33, 35, 46.at n=57A095392
- A Pascal triangle with an Eulerian-number shift: p(x,n)=If[n < 1, (x + 1)^(n + 1), (x + 1)^(n + 1) + (1 - x)^(n + 1)*PolyLog[ -n, x]].at n=49A147290
- A Pascal triangle with an Eulerian-number shift: p(x,n)=If[n < 1, (x + 1)^(n + 1), (x + 1)^(n + 1) + (1 - x)^(n + 1)*PolyLog[ -n, x]].at n=50A147290
- Denominator of Bernoulli_n multiplied by the sum of the associated inverse primes in the Staudt-Clausen theorem, n=1, 2, 4, 6, 8, 10,...at n=15A166306
- Exponential (or binomial) half-convolution of A000045 (Fibonacci) with itself.at n=10A203578
- a(n) = 384*n + 1.at n=41A229853
- a(n) is numerator of rational z(n) associated with the non-orientable map asymptotics constant p((n+1)/2).at n=5A278120
- Largest finite number of distinct words arising in Watanabe's tag system {00, 1011} applied to a binary word w, over all starting words w of length n.at n=30A291067
- Largest finite number of distinct words arising in Watanabe's tag system {00, 1011} applied to a binary word w, over all starting words w of length n.at n=32A291067
- Numbers k such that 1 is in the transitive closure of the map x -> A353313(x) when starting iterating from x=k.at n=52A353306
- Expansion of (1/x) * Series_Reversion( x/(x+1/(1-x-x^4)) ).at n=8A370798
- a(n) = Sum_{k=1..n} sigma( (n/gcd(k,n))^2 ).at n=24A372227