6516
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 16562
- Proper Divisor Sum (Aliquot Sum)
- 10046
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2160
- Möbius Function
- 0
- Radical
- 1086
- Omega Function (Ω)
- 5
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 44
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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) = a(n-1) + a(n-9) for n >= 9; a(n) = 1 for n=0..7; a(8) = 2.at n=49A005711
- Theta series of direct sum of 3 copies of hexagonal lattice.at n=19A008654
- Linear recursion relative of Shallit sequence S(2,6).at n=7A014010
- Expansion of 1/((1-x)(1-11x)(1-12x)).at n=3A016268
- Expansion of 1/(1 - x^9 - x^10 - ...).at n=59A017903
- Define the Shallit sequence S(a_0,a_1) by a_{n+2} is the least integer > a_{n+1}^2/a_n for n >= 0. This is S(2,6).at n=7A018906
- a(n) = 3*a(n-1)+a(n-2)-a(n-3)+a(n-6)-a(n-7)+a(n-10)-a(n-11).at n=7A022041
- Numerator of n*(n-3)*(3*n^2-6*n+2)/(3*(n-1)*(n-2)).at n=9A023417
- Theta series of 6-dimensional perfect lattice P6.6 = A6,1.at n=33A029695
- Expansion of Product_{m>=1} ((1+q^(2*m-1))/(1+q^(2*m)))^3.at n=41A029840
- Number of partitions of n with equal number of parts congruent to each of 2, 3 and 4 (mod 5).at n=51A035581
- Numbers n such that n and n+1 are differences between 2 positive cubes in at least one way.at n=8A038594
- Numbers that are divisible by 6 (and 18) and are differences between two cubes in at least one way.at n=21A038852
- Numbers ending with '6' that are the difference of two positive cubes.at n=27A038861
- Numbers k such that phi(x) = k has exactly 7 solutions.at n=37A060670
- a(n) = 3^n - (n+1)*(n+2)/2.at n=8A061982
- Positive numbers whose product of digits is 10 times their sum.at n=35A062043
- a(n) = n^3 - n^2 + n - 1 = (n-1) * (n^2 + 1).at n=19A062158
- Numbers k such that cototient(k) is a square and sets a new record for squares.at n=21A063753
- Natural numbers of the form p^3 - q^3, where p and q are primes.at n=26A086120