15960
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 64
- Divisor Sum
- 57600
- Proper Divisor Sum (Aliquot Sum)
- 41640
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3456
- Möbius Function
- 0
- Radical
- 3990
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 5
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
- 53
- 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 exterior points formed by extending diagonals of n-gon in general position.at n=18A005701
- a(n) = floor(n*(n-1)*(n-2)*(n-3)/9).at n=21A011919
- [ n(n-1)(n-2)(n-3)/11 ].at n=22A011921
- arcsin(tan(x)*arcsin(x))=2/2!*x^2+12/4!*x^4+310/6!*x^6+15960/8!*x^8...at n=3A012377
- sinh(tan(x)*arcsin(x))=2/2!*x^2+12/4!*x^4+310/6!*x^6+15960/8!*x^8...at n=3A012380
- Perimeters of more than one primitive Pythagorean triangle.at n=26A024408
- The convolution matrix of the double factorial of odd numbers (A001147).at n=24A035342
- Fourth column of triangle A035342; related to A045894.at n=6A035520
- Denominators of continued fraction convergents to sqrt(398).at n=7A041757
- Maximization of sums of cubes of integer differences (b_[ i ]-i)^3 over permutations {b_[ i ], for i-1,2,...,n} on first n integers.at n=25A049031
- Number of scalars which can be constructed from the Riemann tensor and metric tensor in n dimensions.at n=20A050297
- There are exactly n integer-sided triangles of area a(n).at n=26A051586
- a(n) = lcm(6n+2, 6n+4, 6n+6).at n=6A061506
- Numbers k such that sigma(k) and sigma(k+1) are nontrivial powers (A065496).at n=12A065522
- a(n) = Sum_{r|n, s|n, t|n, r<s<t} r*s*t.at n=23A067817
- (Sum of digits of n)^5 - (sum of digits^5 of n).at n=17A069965
- Numbers k such that the sign of core(k)-phi(k) is not equal to 2*mu(k)^2-1, where core(k) is the squarefree part of k.at n=26A070237
- A Fibonacci-like model in which each pair of rabbits dies after the birth of their 4th litter: a(n) = a(n-2) + a(n-3) + a(n-4) + a(n-5).at n=24A072465
- a(1)=3; a(2n), a(2n+1) are smallest integers > a(2n-1) such that a(2n-1)^2+a(2n)^2=a(2n+1)^2.at n=11A077034
- Differences between two successive prime powers of prime numbers (A076707) in more than one way.at n=39A077257