6816
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
- 4
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 11328
- 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
- 2240
- Möbius Function
- 0
- Radical
- 426
- Omega Function (Ω)
- 7
- 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
- 18
- Smith Number
- yes
- 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
- Numbers k such that 57*2^k + 1 is prime.at n=23A002274
- a(n) = n*(5*n^2 - 2)/3.at n=16A004466
- a(n) = 3^n + 2^n - 1.at n=8A005056
- Even octagonal numbers: a(n) = 4*n*(3*n-1).at n=24A014642
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly seven 1's.at n=32A020443
- Sum of n plus its prime factors associated with A020700.at n=19A020905
- Number of partitions of n with equal number of parts congruent to each of 1 and 2 (mod 5).at n=44A035556
- Number of partitions of n such that cn(0,5) = cn(1,5) <= cn(2,5) = cn(4,5) <= cn(3,5).at n=64A036862
- Numbers whose base-4 representation contains exactly two 0's and four 2's.at n=24A045051
- First differences of A029767.at n=4A053481
- Consider all integer triples (i,j,k), j,k>0, with binomial(i+2,3)=binomial(j+2,3)+k^3, ordered by increasing i; sequence gives k values.at n=40A054223
- Numbers k such that k^10 == 1 (mod 11^4).at n=4A056094
- Numbers k such that phi(x) = k has exactly 11 solutions.at n=21A060674
- Numbers beginning and ending with their multiplicative digital root.at n=40A064704
- Numbers k such that k+1 is composite and divides 3^k-2^k.at n=18A068410
- Reverse of largest prime factor of n = smallest prime factor of n+1; a(1)=1.at n=7A071393
- Numbers k that divide A062273(k).at n=13A077579
- E.g.f.: exp(-2*x) / (1-x)^2.at n=7A087981
- Triangle read by rows, formed from product of Pascal's triangle (A007318) and Aitken's (or Bell's) triangle (A011971).at n=30A095674
- Imaginary part of absolute Gaussian perfect numbers, in order of increasing magnitude.at n=20A102532