8120
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 21600
- Proper Divisor Sum (Aliquot Sum)
- 13480
- 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
- 2688
- Möbius Function
- 0
- Radical
- 2030
- 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
- 39
- 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) = 2^(3*n+1) - 2*n*(2*n+1).at n=4A003222
- Number of self-dual signed graphs with n nodes. Also number of self-complementary 2-multigraphs on n nodes.at n=7A004104
- a(n) = 2*binomial(n,3).at n=30A007290
- Expansion of tan(sinh(x))*x.at n=4A009683
- The sequence m(n) in A022905.at n=43A022907
- Expansion of 1/((1-x)(1-6x)(1-10x)(1-11x)).at n=3A024434
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = A001950 (upper Wythoff sequence).at n=31A024864
- a(n) = (2nd elementary symmetric function of {1/1, 1/2, ..., 1/n})*(lcm(S))^2, where S = {1,2,...,n}.at n=4A025531
- Least term in period of continued fraction for sqrt(n) is 9.at n=10A031433
- Numbers whose set of base-9 digits is {1,2}.at n=41A032930
- Numbers having three 2's in base 9.at n=35A043463
- Number of 2n-bead balanced binary necklaces which are equivalent to their reversed complement, but not equivalent to their reverse and complement.at n=14A045678
- Exponential transform of Stirling1 triangle A008275.at n=23A055924
- Sum of absolute values of coefficients of expansion of (1-x)(1-x^2)(1-x^3)...(1-x^n).at n=34A061553
- a(n) = 2*a(n-1)^2 - 2*a(n-2)^2 with a(0) = 0, a(1) = 1.at n=5A061999
- Numbers n such that phi(4n+1) = sigma(n).at n=4A067234
- Numbers k such that sigma(k) = phi(k*omega(k)+1).at n=39A067879
- Number of odd entries in A004001 that are <= 2^n.at n=14A095902
- a(n) = 5*n^2 + 3*n.at n=39A126264
- a(1)=2^3*5*7*29=8120; for n>1, a(n) = (-1)sigma(a(n-1)).at n=0A126602