8506
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 12762
- Proper Divisor Sum (Aliquot Sum)
- 4256
- 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
- 4252
- Möbius Function
- 1
- Radical
- 8506
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 78
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Generalized Euler numbers O_n^+(2).at n=7A007976
- Numbers k such that the continued fraction for sqrt(k) has period 89.at n=9A020428
- Fibonacci sequence beginning 1, 8.at n=16A022098
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 12.at n=5A031600
- Number of isomers C_n H_{2n} without double bonds.at n=12A036671
- Numerators of continued fraction convergents to sqrt(711).at n=6A042368
- Numerators of continued fraction convergents to sqrt(720).at n=4A042386
- A Diaconis-Mosteller approximation to the Birthday problem function.at n=38A050255
- Smallest value of x such that M(x) = n, where M() is Mertens's function A002321.at n=30A051400
- Inverse Mertens function: smallest k such that |M(k)| = n, where M(x) is Mertens's function A002321.at n=30A051402
- Number of lucky 4,6 triples <= 10^n.at n=7A055727
- a(n) = 3*a(n-1) - a(n-2) with a(0)=1, a(1)=9.at n=8A055849
- An inverse to Mertens's function: smallest k >= 2 such that Mertens's function |M(k)| (see A002321) is equal to n.at n=31A060434
- a(n) is the number of divisors of n-th even perfect number.at n=18A061645
- Generalized Bell numbers: column 6 of A275043.at n=3A061687
- Expansion of (1-x)/(1+x^2+x^3).at n=48A078032
- Number of perfect rulers with n segments (n>=0).at n=15A103301
- Numbers m such that (1+i)^m - i is a Gaussian prime.at n=23A103329
- Least semiprime s for which the Mertens function M(s) = n.at n=34A123173
- Record indices of the ratio A002375(n) / n (Goldbach conjecture related).at n=34A137820