8561
domain: N
Properties
Digital Properties
- Digit Count
- 4
- 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
- 9792
- Proper Divisor Sum (Aliquot Sum)
- 1231
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7332
- Möbius Function
- 1
- Radical
- 8561
- 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
- 26
- 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 80.at n=28A020419
- Numbers k such that Fib(k) == -13 (mod k).at n=32A023167
- Expansion of 1/((1-3x)(1-6x)(1-8x)(1-12x)).at n=3A028082
- a(n) = floor ( n(n+1)(n+2)(n+3) / (n+(n+1)+(n+2)+(n+3)) ).at n=31A032767
- Surround numbers of a length 2n zig-zag.at n=25A060641
- a(n) = A077708(n+1)/A077708(n).at n=10A077709
- Indices of prime Padovan numbers: values of k such that A000931(k+5) is prime.at n=21A112882
- Irregular triangle read by rows: T(n, k) = coefficients of f(n, x), where f(n, x) = (1-x)^(2*n+2) * Sum_{k >=0} (k^n * x^k).at n=61A141581
- Irregular triangle read by rows: T(n, k) = coefficients of f(n, x), where f(n, x) = (1-x)^(2*n+2) * Sum_{k >=0} (k^n * x^k).at n=67A141581
- 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, -1, 0), (-1, 0, -1), (-1, 0, 1), (0, -1, -1), (1, 1, 1)}.at n=8A149510
- Number of arrangements of 4 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.at n=14A188359
- Fibonacci sequence beginning 13, 6.at n=15A206612
- If, for some m, A098550(m-2) is a prime p and A098550(m) = 7p, add 7p to the sequence.at n=39A253054
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 113", based on the 5-celled von Neumann neighborhood.at n=49A270177
- Numbers n such that the decimal number concat(2,n) is a square.at n=37A273357
- Expansion of 1 / ((1-x)^2*(1-x^2)*(1-x^3)*...*(1-x^7)).at n=28A288342
- Squares where A323809 gets stuck.at n=7A323813
- Nested base shift convergence sequence (NBSC): gives the constant term of the convergence of a number n into a base sequence conversion nest: a(n) = ...FromDigits(IntegerDigits(FromDigits(IntegerDigits(n,2),3),4),5)..., until the result does not change for more iterations.at n=21A326653
- Main diagonal of array in A358304, divided by 2.at n=27A358307
- Positions in Pi where the leader in the race of digits changes.at n=45A361434