9621
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
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 13910
- Proper Divisor Sum (Aliquot Sum)
- 4289
- 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
- 6408
- Möbius Function
- 0
- Radical
- 3207
- Omega Function (Ω)
- 3
- 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
- 60
- 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
- Number of irreducible positions of size n in Montreal solitaire.at n=9A007050
- a(n) = 2*a(n-1) + a(n-2) - a(n-4) - a(n-5) - a(n-6) - a(n-7).at n=10A019486
- Least non-partition into positive n-th powers.at n=9A027609
- Arrange digits of squares in descending order.at n=36A028908
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 44 ones.at n=35A031812
- Arrange digits of cubes in descending order.at n=21A032554
- Interprimes which are of the form s*prime, s=9.at n=29A075284
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (-1, 0, 1), (0, -1, 0), (1, 1, 0)}.at n=8A149532
- Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,1 4,2 polyhexes in any orientation on a planar nXnXn triangular grid.at n=6A155242
- Start with 3. If a, b in sequence, so is ab+1.at n=44A180432
- a(n) = Sum_{i+j=n, i,j >= 1} tau(i)*sigma(j), where tau() = A000005(), sigma() = A000203().at n=58A191831
- Number of arrays of 2n nondecreasing integers in -4..4 with sum zero and equal numbers greater than zero and less than zero.at n=9A203287
- a(n) = Sum_{i=0..n} digsum(i)^3, where digsum(i) = A007953(i).at n=32A231688
- Number of (n+1) X (1+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge or main diagonally.at n=8A251285
- T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every 2X2 subblock having a single 1 or two 1s on the same edge or main diagonally.at n=36A251292
- Numbers n whose square representation in base 10 can be split into three parts whose sum is n.at n=30A254648
- Numbers k such that 9*R_(k+2) - 4*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=19A257039
- Ulam numbers k such that k/3 is also an Ulam number.at n=19A287212
- Ulam numbers u such that 5*u is also an Ulam number.at n=18A287613
- Number of words of length n over the alphabet {0,1,...,10} such that no two consecutive terms have distance 3.at n=4A287834