1683
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 2808
- Proper Divisor Sum (Aliquot Sum)
- 1125
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 960
- Möbius Function
- 0
- Radical
- 561
- Omega Function (Ω)
- 4
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 42
- 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
- no
- Odd
- yes
Appears in sequences
- Expansion of g.f. (1 + x + 2*x^2)/((1 - x)^2*(1 - x^3)).at n=49A000969
- Number of cells of square lattice of edge 1/n inside quadrant of unit circle centered at 0.at n=46A001182
- Crystal ball sequence for 5-dimensional cubic lattice.at n=5A001847
- Central Delannoy numbers: a(n) = Sum_{k=0..n} C(n,k)*C(n+k,k).at n=5A001850
- Expansion of 1 / ((1-x)^2*(1-x^2)*(1-x^3)*(1-x^4)).at n=26A002621
- Triangle of coefficients of Euler polynomials E_2n(x) (exponents in increasing order).at n=41A004172
- Triangle of coefficients of Euler polynomials E_2n(x) (exponents in decreasing order).at n=43A004173
- a(n)=least number m such that m-a(n-1)<>a(j)-a(k) for all j,k less than m; a(1)=1, a(2)=3.at n=39A004979
- Number of factorization patterns of polynomials of degree n over F_2.at n=18A006167
- Number of partitions of n into parts of sizes {a( )} is a(n).at n=37A007209
- Inverse Moebius transform applied twice to squares.at n=40A007433
- Numbers k such that k*18^k + 1 is prime.at n=5A007648
- Number of lattice points inside circle of radius n is 4(a(n)+n)-3.at n=46A007882
- Coordination sequence T1 for Zeolite Code PAU.at n=30A008219
- Square array of Delannoy numbers D(i,j) (i >= 0, j >= 0) read by antidiagonals.at n=60A008288
- Coordination sequence T1 for Zeolite Code RUT.at n=27A009897
- a(0) = 1, a(n) = n^2 + 2 for n > 0.at n=41A010000
- Least d such that period of continued fraction for sqrt(d) contains n (n^2+2 if n odd, (n/2)^2+1 if n even).at n=40A013945
- Expansion of x/(1-3*x-8*x^2).at n=6A015525
- a(n) = n*(7*n - 1)/2.at n=22A022264