13061
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13452
- Proper Divisor Sum (Aliquot Sum)
- 391
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12672
- Möbius Function
- 1
- Radical
- 13061
- 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
- 138
- 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 k such that the continued fraction for sqrt(k) has period 37.at n=32A020376
- Number of compositions (ordered partitions) of n into distinct parts >= 2.at n=32A032022
- Expansion of sum ( q^n / product( 1-q^k, k=1..4*n), n=0..inf ).at n=29A035296
- Number of partitions in parts not of the form 9k, 9k+1 or 9k-1. Also number of partitions with no part of size 1 and differences between parts at distance 3 are greater than 1.at n=51A035940
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 17.at n=12A051982
- a(n)=floor{square((1*n^0+1*n^1+2*n^2+4*n^3)/(1*n^0+2*n^1+1*n^2))}.at n=29A086863
- Numbers n which are divisors of the number produced by concatenating (n-10), (n-9), (n-8), ... (n-1) in that order.at n=3A088872
- Numbers k such that (2*k)!/(2*(k!)^2)+1 is prime.at n=41A112863
- Expansion of x * (x+1) * (x^3-x^2-1) / ((x^2+1) * (x^3+x^2-1)).at n=36A122519
- a(n) = 15*n*(n+1) + 11.at n=29A132208
- Numbers k such that continued fraction of (1 + sqrt(k))/2 has period 17.at n=36A146340
- Triangle T(n,k) read by rows: T(n,k) = (m*n - m*k + 1)*T(n - 1, k - 1) + k*(m*k - (m - 1))*T(n - 1, k) where m = 2.at n=22A166961
- Least number k such that k^n + k +/- 1 are twin primes, or 0 if no such k exists.at n=33A248081
- a(0) = a(1) = a(2) = a(3) = 1; thereafter a(n) = a(n-1) + a(n-2) + a(n-4).at n=19A307677
- Semiprimes p*q such that p*q+p+q, p*q-(p+q), p*q+2*(p+q) and p*q-2*(p+q) are all primes.at n=19A356765
- a(n) = Sum_{k=0..floor(n/4)} binomial(n,k) * binomial(n-3*k,k).at n=15A383523
- a(n) is the number of 5 element sets of distinct integer-sided trapezoids whose base angles are 60 degrees that fill an equilateral triangular grid of side n units formed by directly binary space partitioning 3-trapezoid sets without forming 4-trapezoid sets.at n=34A391203