7980
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 26880
- Proper Divisor Sum (Aliquot Sum)
- 18900
- 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
- 1728
- Möbius Function
- 0
- Radical
- 3990
- Omega Function (Ω)
- 6
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- Convolution of A000203 with itself.at n=25A000385
- Denominator in Feinler's formula for unsigned Bernoulli number |B_{2n}|.at n=9A002444
- Denominators of Cauchy numbers of second type (= Bernoulli numbers B_n^{(n)}).at n=18A002790
- Number of partitions into pairs.at n=4A006200
- a(n) = n*(n-1)*(n-2) (or n!/(n-3)!).at n=21A007531
- Area of more than one Pythagorean triangle.at n=10A009127
- a(n) = n*(n+1)*(2*n+1)*(3*n+1)/6.at n=9A011195
- Partial sums of A011863.at n=13A011888
- a(n) = floor( n*(n-1)*(n-2)/22 ).at n=57A011904
- a(n) = floor(n(n-1)(n-2)(n-3)/18).at n=21A011928
- a(n) = floor( n*(n-1)*(n-2)*(n-3)/22 ).at n=22A011932
- a(n) = n*(13*n + 1)/2.at n=35A022271
- Theta series of A*_20 lattice.at n=31A023932
- Areas of right triangles with coprime integer sides.at n=39A024365
- Ordered areas of primitive Pythagorean triangles.at n=41A024406
- Ordered areas of primitive Pythagorean triangles.at n=42A024406
- Areas of more than one primitive Pythagorean triangle.at n=2A024407
- Expansion of 1/((1-2x)(1-5x)(1-10x)(1-11x)).at n=3A026149
- a(n) = A027113(n, 2n-1).at n=9A027119
- Pair up the numbers.at n=39A030655