11720
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
- 16
- Divisor Sum
- 26460
- Proper Divisor Sum (Aliquot Sum)
- 14740
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4672
- Möbius Function
- 0
- Radical
- 2930
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 3
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
- 37
- 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
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 53.at n=38A031551
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 91 ).at n=37A063364
- Consider the sequence b(k) such that b(k) and sigma(b(k)) end with the same digit in base 10. Sequence gives values of b(k) such that b(k)/k = 10.at n=25A065255
- a(1) = 6; a(n+1) = (a(n)+1)/2 if a(n) odd, or 5*a(n)/2 if a(n) even.at n=31A070870
- McKay-Thompson series of class 40B for the Monster group.at n=47A112179
- a(n)=n^6-n^5-n^4-n^3-n^2-n.at n=5A152030
- Triangle T(n, k, m) = (m*(n-k) + 1)*T(n-1, k-1, m) + (m*k + 1)*T(n-1, k, m) - m*k*(n-k)*T(n-2, k-1, m) with T(n, 0, m) = T(n, n, m) = 1 and m = 5, read by rows.at n=17A157156
- Triangle T(n, k, m) = (m*(n-k) + 1)*T(n-1, k-1, m) + (m*k + 1)*T(n-1, k, m) - m*k*(n-k)*T(n-2, k-1, m) with T(n, 0, m) = T(n, n, m) = 1 and m = 5, read by rows.at n=18A157156
- a(1)=1. a(n) = A005179(d(a(n-1))) + a(n-1), where d(n) = the number of divisors of n, and A005179(n) is the smallest positive integer with exactly n divisors.at n=44A175300
- Number of line segments connecting exactly 9 points in an n x n grid of points.at n=38A177725
- A014486-codes for the compact representation of Beanstalk-tree, growing by two natural numbers at time, starting from the tree of one internal node (1) and two leaves (2 and 3), with the lesser numbers coming to the left hand side.at n=6A218780
- For n > 1 the sum of t := floor(n/2) + 1 consecutive previous terms, the leading t terms when n is even, the immediately-preceding t terms when n is odd; a(0) = 0, a(1) = 1.at n=48A238834
- Number of chains in the poset of all odd-sized subsets of {1,2,...,n} ordered by inclusion.at n=8A260504
- Number of dissections of an n-gon into 3- and 4-gons counted up to rotations and reflections.at n=9A290646
- G.f. satisfies A(x) = 1 + x / (1 - x*A(x))^5.at n=7A365115
- Number of labeled 3-nilpotent semigroups of order n.at n=4A383871