jmc

We have that $A+B+C+D=64$. Substituting everything in terms of $C$, we find that $(3C-3)+(3C+3)+C+(9C)=64$, which means that $C=4$. Thus $A=9$, $B=15$, and $D=36$. Therefore our desired answer is $9\cdot 15\cdot 4\cdot 36=\boxed{19440}$.