6909
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 10944
- Proper Divisor Sum (Aliquot Sum)
- 4035
- 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
- 3864
- Möbius Function
- 0
- Radical
- 987
- Omega Function (Ω)
- 4
- 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
- 57
- 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
- no
- Odd
- yes
Appears in sequences
- Coordination sequence for hyperbolic tessellation 3^7 (from triangle group (2,3,7)).at n=8A001354
- Number of column-strict plane partitions of n.at n=14A005986
- Largest number not the sum of distinct n-th-order polygonal numbers.at n=25A007419
- Fibonacci sequence beginning 0, 7.at n=16A022090
- Number of Boolean functions of n variables and rank 3 from Post class F(5,inf).at n=6A051375
- Numbers primitive with respect to having more than one factorization into S-primes. See related sequences for definition.at n=37A057950
- Sum_{i=0..2*A053645(n)} (C(2*A053645(n),i) mod 2)*A000045(n-i) [where C(r,c) is the binomial coefficient (A007318) and A000045(n) is the n-th Fibonacci number].at n=20A075149
- a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A001405(k) = C(k, floor(k/2)) equals n.at n=15A081394
- a(1) = 1, a(n) = smallest multiple of n such that the concatenation (n>1) a(n)a(n-1)... a(2) a(1) is a prime.at n=48A089330
- a(n) is the area of the triangle with sides prime(n), prime(n+2) and prime(n+4), rounded down to the nearest integer.at n=26A096384
- Array read by antidiagonals: T(n,k) = variant of Knuth's Fibonacci (or circle) product of n and k (A101330).at n=38A101385
- Array read by antidiagonals: T(n,k) = variant of Knuth's Fibonacci (or circle) product of n and k (A101330).at n=42A101385
- Third row of array in A101385.at n=6A101645
- Triangle, read by rows, where the g.f. of column n, C_n(x), equals the g.f. of row n, R_n(x), divided by (1-x)^(n+1)*(1-x^2)^n, for n>=0; e.g., C_n(x) = R_n(x)/(1-x)^(n+1)/(1-x^2)^n.at n=59A114176
- a(n) = floor((Pi + e)^n).at n=5A121831
- Number of reduced words of length n in the Weyl group E_7 on 7 generators and order 2903040.at n=11A162493
- Diagonal sums of the exponential Riordan array [1+x*arctanh(x), x], A166357.at n=4A166359
- Partial sums of near-repdigit primes A056710.at n=18A172983
- Partials sums of A001694.at n=36A174172
- a(n) = a(n-1) + floor(a(n-2)/3) with a(0)=2, a(1)=3.at n=36A182229