6478
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
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10080
- Proper Divisor Sum (Aliquot Sum)
- 3602
- 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
- 3120
- Möbius Function
- -1
- Radical
- 6478
- 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
- 124
- 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 even period and if the last term of the periodic part is deleted the central term is 80.at n=3A031578
- a(n) = prime(n)*prime(n+1) - prime(n).at n=21A037166
- Indices of triangular numbers which are also 9-gonal.at n=3A048908
- Numbers n such that 131*2^n-1 is prime.at n=14A050591
- a(n) = T(n,n-3), array T as in A055818.at n=30A055820
- McKay-Thompson series of class 42d for Monster.at n=45A058678
- Numbers k such that sopf(k) = 2*sopf(k+1), where sopf(k) = A008472.at n=10A064112
- Zero, together with positive numbers k such that prime(k) + k is a square.at n=27A064371
- a(n) = (prime(n)+1)*(prime(n+1)+1)/4.at n=36A079079
- Squarefree kernel of (prime(n)+1)*(prime(n+1)+1)/4.at n=36A079093
- Squarefree numbers of the form (prime(k)+1)*(prime(k+1)+1)/4.at n=9A079095
- Diagonal of triangular spiral in A051682.at n=37A081270
- a(n) = n^3 - n^2 - n - 1.at n=19A083074
- a(n) = (3*n+1)*(3*n+4).at n=26A085001
- Numbers n such that numerator(Bernoulli(2*n)/(2*n)) is different from numerator(Bernoulli(2*n)/(2*n*(2*n+1))).at n=22A090177
- a(n) = sigma_3(n) - sigma_2(n) - sigma_1(n).at n=18A092350
- Numbers n such that sigma(n)=sigma(d_1)*sigma(d_2)*...*sigma(d_k) where d_1 d_2 ... d_k is the decimal expansion of n.at n=16A098771
- Numbers n such that prime(n) + n is a perfect power.at n=32A107605
- Number of ways to build a contiguous building with n LEGO blocks of size 3 X 3 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.at n=5A123836
- a(n) = lcm(prime(n)+1, prime(n+1)+1) / 2.at n=36A124691