9918
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 23400
- Proper Divisor Sum (Aliquot Sum)
- 13482
- 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
- 3024
- Möbius Function
- 0
- Radical
- 3306
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 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
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Maximal number of pieces obtained by slicing a torus (or a bagel) with n cuts: (n^3 + 3*n^2 + 8*n)/6 (n > 0).at n=38A003600
- Coordination sequence for sigma-CrFe, Position Xa.at n=25A009962
- Numbers k such that k(k+1)(k+2)...(k+9) / (k+(k+1)+(k+2)+...+(k+9)) is an integer.at n=33A032782
- Multiplicity of highest weight (or singular) vectors associated with character chi_8 of Monster module.at n=41A034396
- Number of permutations P of {1,2,...,n} such that P(1)=1 and |P^-1(i+1)-P^-1(i)| equals 1 or 2 for i=1,2,...,n-1.at n=23A038718
- McKay-Thompson series of class 42A for Monster.at n=49A058671
- Treated as strings, n begins with Floor(sqrt(n)).at n=41A069086
- Row sums in A083167.at n=18A083170
- a(n) is the largest number such that all of a(n)'s length-n substrings are distinct and divisible by 87.at n=3A093287
- Multiples of 18 containing a 18 in their decimal representation.at n=22A121038
- Base-2 logarithm of (n-th even superperfect number divided by 2^n).at n=21A134712
- Twice nonagonal numbers (or twice 9-gonal numbers): a(n) = n*(7*n-5).at n=38A139268
- Number of paths of a chess Rook in a cube, from (1,1,1) to (n,n,n), where the rook may move in steps that are multiples of (1,0,0), (0,0,1), or (0,0,1).at n=3A144045
- Six times hexagonal numbers: 6*n*(2*n-1).at n=29A152746
- a(n) = Sum_{k=1..n} (k+2)!/k! = Sum_{k=1..n} (k+2)*(k+1).at n=29A180118
- Table A(d,n) of the number of paths of a chess rook in a d-dimensional hypercube from (0...0) to (n...n) where the rook may move in steps that are multiples of (1,0..0), (0,1,0..0), ..., (0..0,1).at n=18A181731
- Number of -2..2 arrays x(0..n-1) of n elements with zero sum, adjacent elements differing by more than one, and elements alternately increasing and decreasing.at n=12A200186
- Number of ways to place k nonattacking bishops on an n X n board, sum over all k>=0.at n=5A201862
- Number of nX2 0..2 arrays with exactly floor(nX2/2) elements equal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..2 order.at n=5A222885
- T(n,k)=Number of nXk 0..2 arrays with exactly floor(nXk/2) elements equal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..2 order.at n=22A222889