13261
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13500
- Proper Divisor Sum (Aliquot Sum)
- 239
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13024
- Möbius Function
- 1
- Radical
- 13261
- Omega Function (Ω)
- 2
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 76
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Conjectured formula for irreducible 6-fold Euler sums of weight 2n+16.at n=27A019459
- Numbers k such that the continued fraction for sqrt(k) has period 79.at n=11A020418
- Centered 17-gonal numbers: (17*n^2 - 17*n + 2)/2.at n=39A069130
- Number of distinct products i*j*k*l for 1 <= i <= j <= k <= l <= n.at n=33A100437
- Numbers n such that 1+2n+3n^2 is a triangular number.at n=5A122513
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 0), (0, 0, 1), (0, 1, -1), (1, 1, 1)}.at n=7A150865
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 3,0,1,1,0,1,0 for x=0,1,2,3,4,5,6.at n=5A197752
- a(n) = floor(5*prime(n)^2 / 4).at n=26A246010
- a(n) = floor( prime(n)^3 / (n*log(n)) ).at n=27A259648
- Centered 10-gonal numbers which are products of two primes.at n=22A367792
- Triangle read by rows: T(n,k) is the number of ballotlike paths ending at (n, k), with 0 <= k <= n.at n=57A375085
- Square array A(n, k) = A048720(A065621(sigma((2n-1)^2)), sigma((2k-1)^2)), read by falling antidiagonals, (1,1), (1,2), (2,1), (1,3), (2,2), (3,1), etc.at n=52A379221