6685
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9216
- Proper Divisor Sum (Aliquot Sum)
- 2531
- 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
- 4560
- Möbius Function
- -1
- Radical
- 6685
- 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
- Spiral sieve using Fibonacci numbers.at n=18A005624
- Expansion of 1/((1-3x)(1-10x)(1-12x)).at n=3A018207
- Numbers whose base-9 representation has exactly 5 runs.at n=30A043634
- Numbers of the form p*q*r where p,q,r are distinct odd palindromic primes (odd terms from A002385).at n=29A046405
- McKay-Thompson series of class 39C for Monster.at n=42A058661
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 71 ).at n=32A063344
- Partial sums of A001158: Sum_{j=1..n} sigma_3(j).at n=11A064603
- McKay-Thompson series of class 39C for the Monster group with a(0) = 1.at n=42A094362
- Numbers k such that k^6+6 is prime.at n=32A109836
- Expansion of 1/((1-x)*(1-x^2)*(1-x^3)*(1-x^4))^2.at n=20A117486
- Numbers with composite sum of digits and prime sum of cubes of digits.at n=30A121642
- A triangular array distributing the values of sequence A072213 (cf. A115994).at n=18A128626
- Indices k such that A020509(k)=Phi[k](-10) is prime, where Phi is a cyclotomic polynomial.at n=49A138920
- Number of ON states after n generations of cellular automaton based on f.c.c. lattice with each cell adjacent to its twelve neighbors.at n=20A151776
- Triangle T(n,k) read by rows: T(n,1) = T(n,n)=1, otherwise T(n,k) = (3n-3k+1)*T(n-1,k-1) + k*(3k-2)*T(n-1,k), 1<=k<=n.at n=16A166962
- Index of the smallest prime greater than (6n+1)^2.at n=43A174321
- G.f. satisfies: A(x) = ( Sum_{n>=0} q^(n*(n+1)/2) )^4 where q=x*A(x)^2.at n=4A194044
- Compositions with superdiagonal growth: number of compositions (p0, p1, p2, ...) of n with pi - p0 >= i.at n=34A238861
- T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=22A240460
- Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=5A240461