8109
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 12636
- Proper Divisor Sum (Aliquot Sum)
- 4527
- 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
- 4992
- Möbius Function
- 0
- Radical
- 2703
- Omega Function (Ω)
- 4
- 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
- 158
- 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
- no
- Odd
- yes
Appears in sequences
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); A000099 gives values of n where |P(n)| sets a new record; sequence gives A(A000099(n)).at n=25A000323
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 20.at n=8A031698
- Multiplicity of highest weight (or singular) vectors associated with character chi_11 of Monster module.at n=42A034399
- Denominators of continued fraction convergents to sqrt(75).at n=11A041133
- Denominators of continued fraction convergents to sqrt(300).at n=5A041565
- Numbers whose base-5 representation contains exactly two 2's and three 4's.at n=35A045288
- Numbers n such that Catalan(n)+1 is prime.at n=31A053429
- a(n) = 100*n^2 + n.at n=8A055438
- Numbers k such that the period of the continued fraction for sqrt(3)*k is 2.at n=47A064933
- Numbers k that divide 2^(k+3) - 1.at n=37A069927
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=37A090121
- Smaller of two consecutive lucky numbers with the same digital sum.at n=32A118566
- a(1) = 335; a(n) is the smallest k > a(n-1) such that k*A002110(n)^30 - 1 is prime.at n=35A119760
- Poincaré series [or Poincare series] P(C#_{3,2}; x).at n=24A124630
- a(n) = smallest multiple of n which is > exp(n).at n=8A128105
- Number of degree n polynomials over GF(2) (with nonzero constant term) at Hamming distance 1 from some irreducible polynomial.at n=14A128901
- Numerator of Sum_{k=1..n} k*H_{n+k} where H_m = Sum_{i=1..m} 1/i.at n=8A144654
- Numbers n with property that A077116(n) is nonzero square.at n=39A154101
- a(n) = 81*n^2 + 9.at n=9A157888
- Expansion of (1+8*x)/(1-x-81*x^2).at n=4A158609