6168
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
- 16
- Divisor Sum
- 15480
- Proper Divisor Sum (Aliquot Sum)
- 9312
- 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
- 2048
- Möbius Function
- 0
- Radical
- 1542
- Omega Function (Ω)
- 5
- 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
- 36
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = a(n-1) + n*a(n-2); a(0) = a(1) = 1.at n=9A000932
- Number of n-step polygons on f.c.c. lattice.at n=4A005398
- Number of primitive n-node animals on b.c.c. lattice.at n=5A007196
- Sum of gcd(x, y) for 1 <= x, y <= n.at n=47A018806
- Exactly half of first a(n) terms of A022300 are 1's (not known to be infinite).at n=38A025513
- Number of partitions of n into an even number of parts.at n=34A027187
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 19.at n=35A031517
- Expansion of Product_{k>=1} (1 + 3*x^k).at n=21A032308
- Number of cycle types of conjugacy classes of all even permutations of n elements.at n=34A046682
- a(n) = Xpower(n,3).at n=30A048732
- Expansion of e.g.f. (2-5*x)/((1-x)*(1-4*x)).at n=4A052695
- Number of unlabeled graphs with n nodes and an odd number of edges.at n=7A054960
- McKay-Thompson series of class 52a for Monster.at n=57A058707
- Numbers which are the sum of their proper divisors containing the digit 0.at n=34A059461
- a(n) is the position of A050614(n) in A062877.at n=12A062878
- When expressed in base 3 and then interpreted in base 8, is a multiple of the original number.at n=36A062889
- Solutions to phi(gpf(x)) - gpf(phi(x)) = 254 = c are special multiples of 257, x = 257k, where largest prime factors of factor k were observed from {2, 3, 5, 17}. See solutions to other even cases of c (=A070813): A007283 for 0, A070004 for 2, A070814 for 14, A070816 for 65534.at n=13A070815
- Triangle read by rows where T(n+1,k)=T(n,k)+n*T(n-1,k) starting with T(n,n)=1 and T(n,k)=0 if n<k.at n=56A070895
- Sum of the coefficients of the n-th Moebius polynomial, M(n,x), where M(n,-1) = mu(n), the Moebius function of n.at n=11A074587
- Least positive integers, all distinct, that satisfy sum(n>0,1/a(n)^z)=0, where z=(60+I*11)/61.at n=16A084804