13813
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14560
- Proper Divisor Sum (Aliquot Sum)
- 747
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13068
- Möbius Function
- 1
- Radical
- 13813
- 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
- 45
- 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
- Numbers n such that n is a substring of its square (both n and n squared in base 4) (written in base 10).at n=26A018828
- Numbers n such that n is a substring of its square in base 8 (written in base 10).at n=14A018832
- Numbers whose base-4 representation contains exactly four 1's and three 3's.at n=25A045132
- Numbers k such that |2^k - k^5| is prime.at n=13A075981
- a(n) = Sum_{k=0..floor(n/6)} C(n-3k,3k) * 2^k.at n=20A100135
- Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n starting with exactly k consecutive pyramids. A pyramid in a Dyck path is a factor of the form U^j D^j (j>0), starting at the x-axis. Here U=(1,1) and D=(1,-1). This definition differs from the one in A091866.at n=67A127156
- 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, 1), (0, 1, -1), (0, 1, 1), (1, -1, 1)}.at n=8A149394
- Numbers k such that (16*10^k + 161)/3 is prime.at n=26A273265
- a(n) is the number of permutations of length n that avoid the pattern 231 and the mesh pattern (12, 281) or the same sequence for the mesh patterns (12, 313), (12, 345), (12, 377), (12, 401), (12, 403), (12, 465), (12, 467).at n=10A289449