6518
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
- 9780
- Proper Divisor Sum (Aliquot Sum)
- 3262
- 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
- 3258
- Möbius Function
- 1
- Radical
- 6518
- 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
- 49
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = 1 + n/2 + 9*n^2/2.at n=38A006137
- 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 80.at n=8A031578
- Becomes prime or 4 after exactly 8 iterations of f(x) = sum of prime factors of x.at n=19A048130
- Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 6 sites wide.at n=34A058367
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 77 ).at n=29A063350
- Triangle read by rows: Each row is constructed by forming the partial sums of the previous row, reading from the right and at every third row repeating the final term.at n=38A099961
- Triangle read by rows: Each row is constructed by forming the partial sums of the previous row, reading from the right and at every third row repeating the final term.at n=39A099961
- First column (also row sums) of triangle in A099961.at n=13A099962
- F(n)_n where F() = Fibonacci numbers A000045.at n=16A122633
- a(n) = T(p(n)) - p(T(n)) = Commutator[triangular numbers, primes] at n.at n=34A123907
- Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(n) = A147952(n).at n=27A147953
- A(n,k) for n >= k in triangular ordering, where A(n,k) is the number of compositions (ordered partitions) of n into k parts, with the first part greater than or equal to all other parts.at n=53A156042
- a(n) = Sum_{d|n} d*binomial(n/d+d-2,d-1).at n=48A157020
- Number of distinct solutions of sum{i=1..6}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1.at n=5A180777
- T(n,k)=number of distinct solutions of sum{i=1..k}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1.at n=60A180782
- Number of different ways to divide an n X 5 rectangle into subsquares, considering only the list of parts.at n=44A187753
- a(n) = n^3 - 4*n^2 + 6*n - 2.at n=17A188377
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 5,5,1,0,1,1,0 for x=0,1,2,3,4,5,6.at n=5A197966
- Numbers n such that (k!+n)/(k+n) is prime for some k.at n=13A242916
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 657", based on the 5-celled von Neumann neighborhood.at n=16A273336