13581
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
- 8
- Divisor Sum
- 20160
- Proper Divisor Sum (Aliquot Sum)
- 6579
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9036
- Möbius Function
- 0
- Radical
- 1509
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 37
- 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
- Padovan sequence (or Padovan numbers): a(n) = a(n-2) + a(n-3) with a(0) = 1, a(1) = a(2) = 0.at n=40A000931
- For n = 0, 1, 2, a(n) = n; thereafter, a(n) = 2*a(n-1) - a(n-2) + a(n-3).at n=18A005314
- Pisot sequences E(3,7), P(3,7).at n=10A010912
- Take every 5th term of Padovan sequence A000931, beginning with the sixth term.at n=7A012772
- Take every 5th term of Padovan sequence A000931, beginning with the first term.at n=8A012864
- Numbers k such that sigma(k) = sigma(k+4).at n=18A015863
- Pisot sequences E(5,9), P(5,9).at n=14A020713
- Pisot sequences E(7,9), P(7,9).at n=27A020720
- Generalized Catalan numbers: a(0) = 1, a(n) = a(n-1) + Sum_{k=1..n-4} a(k) * a(n-k).at n=14A023425
- Expansion of (1 - x)/(1 - x^2 - x^3).at n=42A078027
- Arithmetic derivative of (prime(n)+1)*(prime(n+1)+1)/4.at n=39A079094
- a(n+3) = 3*a(n+2) - 2*a(n+1) + a(n).at n=11A095263
- Number of n-th generation triangles in the tiling of the hyperbolic plane by triangles with angles {Pi/2, Pi/3, 0}.at n=30A096231
- Expansion of (1+x)^2/((1+x)^2+x^3).at n=20A099529
- a(n)=the sum of the (1,2)- and (1,3)-entries of the matrix P^n + T^n, where the 3 X 3 matrices P and T are defined by P=[0,1,0;0,0,1;1,0,0] and T=[0,1,0;0,0,1;1,1,0].at n=36A109524
- Padovan numbers for which the digital root is also a Padovan number.at n=28A117598
- Padovan numbers for which the multiplicative digital root is also a Padovan number.at n=25A117600
- Padovan numbers which can be divided by their digital root.at n=22A117602
- Diagonal sums of Bessel related triangle A122848.at n=17A122849
- Expansion of (1+x)/(1-x^2+x^3).at n=42A124745