6906
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
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13824
- Proper Divisor Sum (Aliquot Sum)
- 6918
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 2300
- Möbius Function
- -1
- Radical
- 6906
- Omega Function (Ω)
- 3
- 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
- 44
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 68.at n=21A020407
- Numbers whose sum of divisors is a cube.at n=35A020477
- "BIJ" (reversible, indistinct, labeled) transform of 1,2,3,4,...at n=5A032114
- Dirichlet convolution of d(n) (number of divisors) with Fibonacci numbers.at n=19A034772
- Numbers whose base-4 representation contains exactly four 2's and two 3's.at n=20A045155
- a(n) = T(2n-1,n), array T given by A048225.at n=44A048234
- Least k such that A052343(k)=n.at n=8A052345
- Smallest number which is the sum of two positive triangular numbers in exactly n different ways.at n=8A052346
- Indices of A052343 (ways to write n as sum of two triangular numbers) where record values are reached.at n=6A052348
- Indices of A052344 (ways to write n as sum of two nonzero triangular numbers) where record values are reached.at n=6A053587
- Numbers n occurring in binary representation of n*(n+1)/2.at n=35A092734
- A sequence generated from the Narayana triangle considered as a matrix, or from Pascal's triangle.at n=5A095266
- Triangle, read by rows, such that column n equals the row sums of A001263^n, which is the n-th matrix power of the Narayana triangle A001263, for n>=0.at n=50A105556
- Numbers k such that the k-th semiprime == 11 (mod k).at n=12A106136
- Largest number that is not the sum of four (2n+1)-gonal numbers.at n=5A118368
- 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, 0, 0), (0, -1, 0), (0, 1, 0), (1, 1, 0), (1, 1, 1)}.at n=6A151237
- Numbers k such that k^81*(k^81+1)+1 is prime.at n=29A153442
- a(n) = a(n-1) + a(n-2) - [a(n-4)/4] - [a(n-5)/2] - [a(n-6)/4].at n=22A173597
- Euler transform of composite numbers.at n=8A197132
- (A209982)/2.at n=37A209983