9000
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 30420
- Proper Divisor Sum (Aliquot Sum)
- 21420
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2400
- Möbius Function
- 0
- Radical
- 30
- Omega Function (Ω)
- 8
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 47
- 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
- yes
- Achilles Number
- yes
- Perfect Power
- no
- Smooth Number
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Powers of 3 written in base 27.at n=11A004669
- Smallest k such that phi(x) = k has exactly n solutions, n>=2.at n=31A007374
- a(n) = floor(n/4)*floor((n+1)/4)*floor((n+2)/4)*floor((n+3)/4).at n=39A008233
- Erroneous version of A342587.at n=19A008285
- Numbers k such that k^2 and k have same last 3 digits.at n=36A008853
- Smallest k such that phi(x) = k has exactly n solutions, n>=0 with Carmichael conjecture.at n=33A014573
- Inverse Euler transform of A000931.at n=45A018243
- Numbers of form 3^i*10^j, with i, j >= 0.at n=23A025616
- Numbers of form 9^i*10^j, with i, j >= 0.at n=13A025635
- a(n) = n^3 + (n+1)^3 + (n+2)^3 + (n+3)^3 + (n+4)^3.at n=10A027604
- Expansion of 1/((1-4x)(1-7x)(1-8x)(1-11x)).at n=3A028147
- Numbers k such that k^2 has digits in nonincreasing order.at n=34A028821
- Numbers k whose decimal representation, read as a base-20 value and divided by k, yields an integer.at n=43A032571
- a(n) = 10*n^2.at n=30A033583
- Theta series of lattice A_2 tensor D_5 (dimension 10, det. 3888, min. norm 4).at n=6A033697
- Multiplicity of highest weight (or singular) vectors associated with character chi_65 of Monster module.at n=37A034453
- Numbers that contain only one nonzero digit.at n=35A037124
- Numbers having three 0's in base 10.at n=8A043491
- Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2) = k; sequence gives values of k.at n=37A048191
- Triangle read by rows: T(n,k) = k!*binomial(n-1,k-1)*Stirling2(n,k), 1 <= k <= n.at n=19A048743