9640
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 21780
- Proper Divisor Sum (Aliquot Sum)
- 12140
- 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
- 3840
- Möbius Function
- 0
- Radical
- 2410
- Omega Function (Ω)
- 5
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 21
- 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
- Number of nonequivalent dissections of an n-gon into 3 polygons by nonintersecting diagonals rooted at a cell up to rotation and reflection.at n=39A003452
- 4-dimensional analog of centered polygonal numbers.at n=16A006325
- a(n) = least m such that if r and s in {1/2, 1/5, 1/8, ..., 1/(3n-1)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=43A024837
- Arrange digits of 2^n in descending order.at n=12A028910
- Arrange digits of cubes in descending order.at n=16A032554
- Second pentagonal numbers with even index: a(n) = n*(6*n+1).at n=40A049453
- McKay-Thompson series of class 39B for Monster.at n=44A058660
- Number of zero-bit dominant primes (A095071) in range ]2^n,2^(n+1)].at n=18A095019
- Number of A095317-primes in range ]2^n,2^(n+1)].at n=18A095327
- a(1)=1. a(n) = a(n-1) + sum of the squares which are among the first (n-1) terms of the sequence.at n=37A101135
- Numbers k such that k and k^2 use only the digits 0, 2, 4, 6 and 9.at n=16A136905
- 1/Product_{n>=1} (1 - a(n)*x^n) = 1 + Sum_{k>=1} F(k+1)*x^k = 1/(1-x-x^2), where F(n) = A000045(n) (Fibonacci numbers).at n=25A157162
- Row sums of triangle T(j,k) = (j^k) mod (j*k) for 1 <= k <= j (see A096133).at n=39A157351
- a(n) = (11*n^2 + 19*n + 10)/2.at n=41A160749
- Number of 4-step left-handed knight's tours (moves only out two, left one) on an n X n board summed over all starting positions.at n=19A187174
- Number of isomorphism classes of nanocones with 3 pentagons and a nearsymmetric boundary of length n.at n=29A198014
- a(n) = 2^n mod n^3.at n=21A233442
- a(n) = n*(n + 1)*(17*n - 14)/6.at n=15A237617
- Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 3 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 3 4 6 or 7.at n=5A252123
- Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 3 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 3 4 6 or 7.at n=0A252128