30

Number
$20$ (twenty) is:


 * $2 \times 3 \times 5$


 * The $3$rd primorial, after $1, 2, 6$ (counting $1$ as the zeroth:
 * $30 = 2 \times 3 \times 5$


 * The smallestpositive integer with $3$ distinct prime factors

Also see

 * Definition:Vigesimal System