9812
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 18816
- Proper Divisor Sum (Aliquot Sum)
- 9004
- 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
- 4440
- Möbius Function
- 0
- Radical
- 4906
- 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
- 42
- 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
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 18.at n=10A031696
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 91 ).at n=31A063364
- Numbers k such that z(k) = j(k), where z(k) = sopf(k - d(k)), j(k) = d(sopf(k) + k), sopf(k) = A008472(k) and d(k) = A000005(k).at n=17A063961
- Number of primes of the form 30k + 7 less than 10^n.at n=5A091166
- Numbers k for which 8*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=6A096508
- A card-arranging problem: values of n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a fifth power for every i.at n=35A096906
- Start with 1 and repeatedly reverse the digits and add 67 to get the next term.at n=34A118214
- a(n) = 5*n^2 + 3*n.at n=43A126264
- Number of ways to pair up {2..2n+1} so the sum of each pair is prime.at n=9A134293
- a(n) = 121*n^2 + 11.at n=9A158536
- Number of (n+1) X (7+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.at n=10A253158
- Coordination sequence for (3,3,4) tiling of hyperbolic plane.at n=23A265071
- Numbers n such that Bernoulli number B_{n} has denominator 690.at n=12A272186
- Number of compositions (ordered partitions) of n into heptagonal numbers (A000566).at n=43A322799
- Number of Aut(G)-orbits on G-characters that come from Riemann surfaces of genus n.at n=27A347373
- T(n, k) is the total number of symmetric peaks in all partitions of n with exactly k blocks, n >= 3, 2 <= k <= n-1.at n=29A373288
- Even integers x such that x + sqrt(y) = sqrt(x || y), where || denotes decimal concatenation and y is a perfect square.at n=36A390123