13908
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 34720
- Proper Divisor Sum (Aliquot Sum)
- 20812
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 6954
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- 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
- a(n)= 5*(n-1)*a(n-1) -(n-1)*a(n-2), with a(0)=0, a(1)=1.at n=5A108207
- Numbers k such that k*(k+1)-1 and k*(k+1)+1 are twin primes and k*(k+3)-1 and k*(k+3)+1 are also twin primes.at n=12A138303
- Number of nondecreasing strings of numbers x(i=1..7) in -n..n with sum x(i)^3 equal to 0.at n=25A188281
- Number of ways to place 2 non-attacking ferses on an n X n board.at n=12A201243
- a(1) = 2; for n>1, a(n) = largest integer such that the sequence b(n) = a(n)^(1/n) is decreasing.at n=18A207976
- Number of (w,x,y,z) with all terms in {1,...,n} and w<=2x and y<3z.at n=12A212512
- Number of partitions of n where the difference between consecutive parts is at most 3.at n=41A238863
- Number of 5Xn 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=9A302518
- Triangle lc(n,k): the number of purely line-connected k-partitions of [n], n>=4, 3<=k<n.at n=22A305874
- Second differences of the overpartitions.at n=32A361298