8511
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11352
- Proper Divisor Sum (Aliquot Sum)
- 2841
- 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
- 5672
- Möbius Function
- 1
- Radical
- 8511
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 202
- 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
- no
- Odd
- yes
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 29.at n=40A031527
- Initial number for record sum of numbers in trajectory of 3x+1 problem.at n=29A033495
- Smallest value of x such that M(x) = n, where M() is Mertens's function A002321.at n=34A051400
- Inverse Mertens function: smallest k such that |M(k)| = n, where M(x) is Mertens's function A002321.at n=34A051402
- a(n) = 4*n^2 - 7*n + 4.at n=46A054567
- An inverse to Mertens's function: smallest k >= 2 such that Mertens's function |M(k)| (see A002321) is equal to n.at n=35A060434
- Number of elements of order 2 in GL(2,Z_n).at n=46A066947
- a(n)=Sum_{j = 0..n} binomial(phi(n),phi(j)).at n=35A073317
- a(1) = 7, a(n) = least k such that concatenation of n copies of k with all previous concatenation gives a prime.at n=45A111475
- Semiprimes in A054567.at n=19A113692
- Number of permutations of length n which avoid the patterns 2413, 3421, 4123.at n=8A116828
- Least semiprime s for which the Mertens function M(s) = n.at n=38A123173
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1000-1000-1111 pattern in any orientation.at n=13A146600
- Toothpick sequence in the three-dimensional grid.at n=45A160160
- a(n) = (n^3 - 3n^2 + 14n - 6)/6.at n=37A180415
- a(n) = 16*n^2 + 2*n + 1.at n=23A204675
- Triangle of coefficients of polynomials v(n,x) jointly generated with A209581; see the Formula section.at n=51A209582
- Positions in A218787 and A218788 of successive distinct values.at n=46A218611
- a(n) = 6*n^2 + 8*n + 1.at n=37A239325
- Numbers n such that n*2^521 - 1 is prime.at n=32A265498