What Is A Heegner Number?

Logic Level 2

$\large \boxed{\phantom0} \: \boxed{\phantom0} \: \boxed{\phantom0} \div \boxed{\phantom0}$

All the digits $6,7,8$ and $9$ are used exactly once to fill in the boxes above to form a ratio of a 3-digit integer and a 1-digit integer. If this ratio is an integer, what is the maximum possible value of this ratio?