6515
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7824
- Proper Divisor Sum (Aliquot Sum)
- 1309
- 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
- 5208
- Möbius Function
- 1
- Radical
- 6515
- 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
- no
- Odd
- yes
Appears in sequences
- Smallest number that requires n iterations of the bi-unitary totient function (A116550) to reach 1.at n=38A005424
- Coordination sequence for alpha-Mn, Position Mn3.at n=21A009952
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite LIO = Liottite (Ca,Na2,K2)9[Al18Si18O72] starting with a T4 atom.at n=5A019030
- Numbers k such that k^2 contains only digits {2,4,5}.at n=8A031154
- Numbers having three 8's in base 9.at n=19A043487
- Number of positive integers <= 2^n of form 3 x^2 + 10 y^2.at n=16A054167
- Numbers whose set of base 6 digits is {0,5}.at n=19A097252
- Maximal number of squares of side 1 in a disk of radius n.at n=45A125228
- Numbers k such that k and k^2 use only the digits 1, 2, 4, 5 and 6.at n=45A136988
- 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, 1), (-1, 0, 1), (0, 1, -1), (0, 1, 0), (1, 0, 1)}.at n=7A150281
- Triangle read by rows, antidiagonals of an array generated from INVERT transforms of variants of (1, 2, 3, ...).at n=54A175011
- Numbers k such that Sum_{j=1..k} j^phi(j) == 0 (mod k).at n=12A227429
- Number of length n+2 0..3 arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=4A253124
- T(n,k)=Number of length n+2 0..k arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=25A253129
- Number of length 5+2 0..n arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=2A253133
- Numerators of a semi-convergent series leading to the second Stieltjes constant gamma_2.at n=4A262384
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 721", based on the 5-celled von Neumann neighborhood.at n=16A273447
- Numbers n such that 11^n is the highest power of 11 dividing A240751(n).at n=30A286006
- Expansion of (1-x^2)/((1-x-x^2)*(1-x-x^4)).at n=17A291311
- G.f. A(x) satisfies: Product_{n=-oo..+oo} 1 + x^n*(1 + A(x)^n)^n = 4.at n=7A294474