8643
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11968
- Proper Divisor Sum (Aliquot Sum)
- 3325
- 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
- 5544
- Möbius Function
- -1
- Radical
- 8643
- Omega Function (Ω)
- 3
- 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
- 171
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Number of immersions of the oriented circle into the oriented plane with n double points and index n-1.at n=8A008984
- Triangle T(n,k) giving number of immersions of the oriented circle into the oriented plane with n double points and index k, k = -n-1, -n+1, ..., n-1, n+1.at n=46A008985
- Triangle T(n,k) giving number of immersions of the oriented circle into the oriented plane with n double points and index k, k = -n-1, -n+1, ..., n-1, n+1.at n=53A008985
- Poincaré series [or Poincare series] for depths of roots in a certain root system.at n=23A019527
- n written in fractional base 10/8.at n=33A024663
- Number of proper factorizations of p1^n*p2^4, where p1 and p2 are distinct primes.at n=14A031127
- Numbers having period-2 6-digitized sequences.at n=32A031357
- 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 29.at n=43A031527
- McKay-Thompson series of class 16C for Monster.at n=16A058516
- Largest k such that n*k is a number that is formed using all the digits of first n numbers. a(n) = A083431(n)/n.at n=4A083432
- Smallest nontrivial multiple of n ending in n. By nontrivial one means a(n) is not equal to n or concatenation of n with itself.at n=42A083466
- a(n) = floor(A093456(n+1)/A093456(n)).at n=8A093455
- Numbers n such that (22^n-1)^2-2 is prime.at n=5A100907
- Consider the array T(n, m) where the n-th row is the sequence of integer coefficients of A(x), where 1<=a(n)<=n, such that A(x)^(1/n) consists entirely of integer coefficients and where m is the (m+1)-th coefficient. This is the row sum of A to the first coefficient of one.at n=19A112285
- Expansion of 1/(1 - x^2 - 2 x^3 + x^4).at n=30A122512
- a(0) = 0; thereafter, a(n+1) = (a(n) - 2)^2 - n.at n=6A143984
- a(n) = 4*n^2 + 12*n + 3.at n=44A153169
- a(n) = 961*n^2 - 2*n.at n=2A158410
- a(n) = Least i in range [A165583(n),A165583(n+1)] for which abs(A165582(i)) gets the maximum value in that range.at n=45A165584
- Sequence by greedy construction satisfying Lucier-Sárközy difference set condition.at n=46A174911