6945
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11136
- Proper Divisor Sum (Aliquot Sum)
- 4191
- 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
- 3696
- Möbius Function
- -1
- Radical
- 6945
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers that are the sum of 6 positive 7th powers.at n=21A003373
- Number of 3-covers of an unlabeled n-set.at n=14A005783
- a(n) = Sum_{j=0..n} j*Fibonacci(j).at n=13A014286
- Numbers k that divide s(k), where s(1)=1, s(j)=21*s(j-1)+j.at n=27A014872
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Lucas numbers), t = (composite numbers).at n=19A024471
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Lucas numbers), t = (composite numbers).at n=18A025091
- Partial sums of primes congruent to 5 mod 6.at n=38A038361
- Coefficients in expansion of Sum_{n >= 1} x^n/(1-x^n)^4.at n=32A059358
- Centered 14-gonal numbers.at n=31A069127
- Number of n-digit twin prime pairs.at n=5A070076
- Number of polyiamonds with 2n cells that tile the plane by translation but not by 180-degree rotation (Conway criterion).at n=9A075217
- Number of n-node triangulations of the nonorientable surface N_5 in which every node has degree >= 5.at n=2A129059
- Numbers of the form 56+p^2 (where p is a prime).at n=22A138690
- Successive differences of A000990.at n=24A147766
- a(n) = 1 - 2*n^2 + 4*n*(1 + 2*n^2)/3.at n=14A168547
- a(n) = (4*n^3 - 6*n^2 + 8*n + 9 + 3*(-1)^n)/12.at n=28A168582
- a(n) = 1 + (1-2^n)*a(n-1) for n > 0, a(0)=0.at n=5A176337
- Parameters n for which the Tate-Shafarevich group Ш of the elliptic curve y^2=x^3-n has order 16.at n=32A179140
- Total number of positive integers below 10^n requiring 13 positive biquadrates in their representation as sum of biquadrates.at n=4A186671
- Let S denote the palindromes in the language {0,1,2,...,n-1}*; a(n) = number of words of length 4 in the language SS.at n=14A187277