1920
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
- 32
- Divisor Sum
- 6120
- Proper Divisor Sum (Aliquot Sum)
- 4200
- 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
- 512
- Möbius Function
- 0
- Radical
- 30
- Omega Function (Ω)
- 9
- Little Omega Function (ω)
- 3
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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 24
- 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
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Number of ways of writing n as a sum of 5 squares.at n=41A000132
- a(n) = Sum_{k=1..n-1} k*sigma(k)*sigma(n-k).at n=9A000441
- Jordan-Polya numbers: products of factorial numbers A000142.at n=37A001013
- Sorted list of orders of Weyl groups of types A_n, B_n, D_n, E_n, F_4, G_2.at n=13A001217
- a(n) = n concatenated with n + 1.at n=18A001704
- Highly abundant numbers: numbers k such that sigma(k) > sigma(m) for all m < k.at n=52A002093
- Denominators of coefficients of log(1+x)/sqrt(1+x).at n=5A002550
- a(n) = 4^n*(2*n+1)!.at n=2A002671
- Denominators of central difference coefficients M_{3}^(2n+1).at n=2A002672
- a(0) = 1; for n > 0, a(n) = 2^(n-1)*n!.at n=5A002866
- Number of Hamiltonian paths in W_5 X P_n.at n=1A003738
- Degrees of irreducible representations of Janko group J3.at n=14A003906
- Degrees of irreducible representations of Janko group J3.at n=13A003906
- Degrees of irreducible representations of Janko group J3.at n=15A003906
- Degrees of irreducible representations of Held group He.at n=11A003912
- Representation degeneracies for boson strings.at n=22A005294
- Number of distinct autocorrelations of binary words of length n.at n=47A005434
- a(n) = n*(n+1)^2/2.at n=15A006002
- Coefficients for numerical integration.at n=1A006685
- Order of group generated by perfect shuffles of 2n cards.at n=4A007346