$ \begin{array}{r|l} 20 & 2\\ 10 & 2\\ 5 & 5\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 24 & 2\\ 12 & 2\\ 6 & 2\\ 3 & 3\\ 1 & \end{array} $
 
$20 * 24 = 2^5 * 5 * 3 = 480$

$ \begin{array}{r|l} 12 & 2\\ 6 & 2\\ 3 & 3\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 25 & 5\\ 5 & 5\\ 1 & \end{array} $
 
$12 * 25 = 2^2 * 5^2 * 3 = 300$

$ \begin{array}{r|l} 164 & 2\\ 82 & 2\\ 41 & 41\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 10 & 2\\ 5 & 5\\ 1 & \end{array} $
 
$164 * 10 = 2^3 * 5 * 41 = 1640$

$ \begin{array}{r|l} 8 & 2\\ 4 & 2\\ 2 & 2\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 125 & 5\\ 25 & 5\\ 5 & 5\\ 1 & \end{array} $
 
$8 * 125 = 2^3 * 5^3 = 1000$

$ \begin{array}{r|l} 125 & 5\\ 25 & 5\\ 5 & 5\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 64 & 2\\ 32 & 2\\ 16 & 2\\ 8 & 2\\ 4 & 2\\ 2 & 2\\ 1 & \end{array} $
 
$125 * 64 = 5^3 * 2^6 = 8000$

$ \begin{array}{r|l} 112 & 2\\ 56 & 2\\ 28 & 2\\ 14 & 2\\ 7 & 7\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 147 & 3\\ 49 & 7\\ 7 & 7\\ 1 & \end{array} $
 
$112 * 147 = 2^4 * 3 * 7^3 = 16464$

$ \begin{array}{r|l} 1001 & 7\\ 143 & 11\\ 13 & 13\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 37 & 37\\ 1 & \end{array} $
 
1001 * 37 = 7 * 11 * 13 * 37 = 37037

$ \begin{array}{r|l} 47 & 47\\ 1 & \end{array} $
 
$ \begin{array}{r|l} 201 & 3\\ 67 & 67\\ 1 & \end{array} $
 
47 * 201 = 3 * 47 * 67 = 9447