15640
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 38880
- Proper Divisor Sum (Aliquot Sum)
- 23240
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5632
- Möbius Function
- 0
- Radical
- 3910
- Omega Function (Ω)
- 6
- 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
- 102
- 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
- Numerator of [x^(2n+1)] of the Taylor expansion -arcsin(cot(x)-coth(x)).at n=4A013553
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 11 ones.at n=34A031779
- a(n) = n(n+7)(n+1)(n^2+2n+12)/120.at n=15A051746
- Let f(x)=(largest digit of x)^(smallest digit of x) + x (A097385). Sequence gives numbers n such that f(n) and f(n+1) are both prime.at n=34A097387
- Diagonal sums of correlation triangle of central binomial coefficients.at n=8A115256
- Column 1 of triangle A118032, where column 1 of the matrix square of A118032 forms a bisection of this sequence.at n=18A118034
- Triangle T, read by rows, equal to the matrix square of A118032 and also equal to a diagonal bisection of A118032; i.e., diagonal n of T equals diagonal 2n of A118032: T(n,k) = A118032(2n-k,k) for n>=k>=0.at n=56A118040
- Column 1 of triangle A118040, which is the matrix square of triangle A118032; also equals a bisection of A118034, which is column 1 of A118032.at n=9A118042
- Site series for first perpendicular moment of 4.8 (bathroom tile) lattice.at n=26A120560
- Numbers k such that k+1, k+3, k+7 and k+9 are all primes.at n=13A125855
- The Wiener index of a chain of n squares joined at vertices (i.e., joined like <><><>...<>; here <> is a square!).at n=16A143943
- a(n) = n*(n-1)*(n+1)*(3*n-2)/12.at n=15A153978
- Number of 3-step king's tours on an n X n board summed over all starting positions.at n=17A186862
- Number of 6-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=12A187176
- T(n,k)=Equals two maps: number of nXk binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..3 nXk array.at n=23A220959
- Equals two maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..3 3Xn array.at n=4A220960
- Dimensions of totally primitive elements of Hopf algebra PMN_2.at n=3A230886
- Number of length n+5 0..2 arrays with no disjoint triples in any consecutive six terms having the same sum.at n=6A247989
- T(n,k)=Number of length n+5 0..k arrays with no disjoint triples in any consecutive six terms having the same sum.at n=34A247995
- Number of length 7+5 0..n arrays with no disjoint triples in any consecutive six terms having the same sum.at n=1A248002