NM Cryptogram

$\large{\begin{array}{ccccccc} && & & & & M&N \\ \times && & & & & M & M \\ \hline & & & & N& M & M&N\\ \end{array}}$

For the above cryptogram, each letter represent a distinct positive single digit integer, find the value of the 4-digit integer, $\overline{NMMN}$ .