8400
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 60
- Divisor Sum
- 30752
- Proper Divisor Sum (Aliquot Sum)
- 22352
- 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
- 1920
- Möbius Function
- 0
- Radical
- 210
- Omega Function (Ω)
- 8
- 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
- yes
- 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
- 34
- 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
- a(n) = 4^n - C(4,3)*3^n + C(4,2)*2^n - C(4,1).at n=6A000919
- Denominator of Sum_{i+j+k=n; i,j,k > 0} 1/(i*j*k).at n=8A002546
- a(n) = (n+1) * (2*n)! / n!.at n=4A002690
- a(n) = (n-1)*n*(n+4)/6.at n=36A005581
- a(n) = n^2*(n^2 - 1)/6.at n=15A008911
- Expansion of e.g.f.: x*cos(log(1+x)).at n=8A009024
- a(n) = n^2*(n+1).at n=20A011379
- cosh(sinh(x)*arcsin(x))=1+12/4!*x^4+240/6!*x^6+8400/8!*x^8...at n=4A012542
- cosh(sinh(x)*arctan(x))=1+12/4!*x^4-120/6!*x^6+8400/8!*x^8...at n=4A012563
- cosh(arcsinh(x)*tan(x))=1+12/4!*x^4+120/6!*x^6+8400/8!*x^8...at n=4A012619
- Even pentagonal numbers.at n=37A014633
- Triangle of numbers T(n,k) = k!*Stirling2(n,k) read by rows (n >= 1, 1 <= k <= n).at n=24A019538
- a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 0, a(1) = 2, a(2) = 1.at n=16A020992
- Convolution of natural numbers with Beatty sequence for tau^2 A001950.at n=25A023542
- a(1) = 7; a(n+1) = a(n)-th composite.at n=30A025011
- a(n) = floor(floor(S3)/floor(S1)), where S3 and S1 are, respectively, the 3rd and first elementary symmetric functions of {sqrt(k), k = 1,2,...,n}.at n=46A025200
- Triangle of the fourth power of the normalized, unsigned Stirling matrix of the first kind.at n=26A027479
- a(n) = n*(n^4-1)/2.at n=5A027484
- a(n) = 5*(n+1)*binomial(n+3,6).at n=4A027791
- Number of days in n years (n=4 is the first leap year).at n=22A033171