8618
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13440
- Proper Divisor Sum (Aliquot Sum)
- 4822
- 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
- 4140
- Möbius Function
- -1
- Radical
- 8618
- 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
- 34
- 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
- yes
- Odd
- no
Appears in sequences
- Trajectory of 3 under map n->45n+1 if n odd, n->n/2 if n even.at n=8A037120
- a(n) = Sum_{k=1..n} phi(k)^2.at n=38A057434
- Number of basis partitions of n+100 with Durfee square size 10.at n=21A069253
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=3, r=3, I={-1,0,1,2}.at n=40A079982
- Number of intersections between a sphere inscribed in a cube and the n X n X n cubes resulting from a cubic lattice subdivision of the enclosing cube.at n=41A085690
- Records in A119451.at n=14A119452
- a(n) = 9n^2 - n.at n=30A154516
- a(n) = 961*n^2 - 31.at n=2A158679
- Number of 4X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 4 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=25A192703
- Number of primes up to 10^n that are of the form (k-2)^2 + (k-1)^2 + k^2.at n=10A218210
- Total sum of parts of multiplicity 6 in all partitions of n.at n=35A222734
- Numbers k such that A000203(x) = k has more than one solution and they all share the same largest prime factor.at n=35A258912
- Number of (n+2) X (6+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.at n=14A258964
- Number of down-up parking functions of length n.at n=7A264963
- Number of broken 1-diamond partitions of n.at n=14A328539
- Number of Sós permutations of {0,1,...,n}.at n=29A330503
- Intersection of A361073 and 2 * A361611.at n=21A361215
- Triangle read by rows: T(n,k) is the number of unlabeled weakly graded (ranked) posets with n elements and rank k.at n=50A361953
- a(n) is the sum of all symmetric peaks in the set of flattened Catalan words of length n.at n=7A372884