13565
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
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 16284
- Proper Divisor Sum (Aliquot Sum)
- 2719
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10848
- Möbius Function
- 1
- Radical
- 13565
- 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
- 182
- 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
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 9.at n=22A051974
- Number of n-step self-avoiding walks on cubic lattice with first step specified.at n=6A078717
- Starting positions of strings of three 4's in the decimal expansion of Pi.at n=13A083615
- Numbers k such that f(k), f(k+1) and f(k+2) are all primes, where f(k) = 8*k^2 + 4*k + 1.at n=42A103777
- Numbers k such that k^3 contains a pandigital substring.at n=10A115933
- Number of permutations P of 1..n such that in P and in the inverse of P, every pair of adjacent numbers and the first and last number, are relatively prime.at n=10A117542
- Sums of Pythagorean sextuples in increasing order: The sums of sets of six natural numbers which correspond to the lengths of the edges of a tetrahedron whose four faces are all different Pythagorean triangles.at n=19A248548
- Semiprime numbers whose digit string can be partitioned into three parts such that the product of the first two parts equals the third part.at n=25A280636
- Number of 2Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 or 4 neighboring 1s.at n=12A297734
- Number of even-length strict integer partitions of 2n+1.at n=34A343942
- Number of strict odd-length integer partitions of 2n + 1.at n=34A346634