\[\boxed{\mathbf{275}.}\]
\[(m - 1) \in Z;\ \ (m - 1)\ \vdots 9:\]
\[m^{3} - 1 = \underset{\vdots 9}{\overset{(m - 1)}{︸}}(m^{2} + m + 1)\]
\[Докажем,\ что\ \left( m^{2} + m + 1 \right)\ \vdots 3.\]
\[m - 1 = 9m_{1} \rightarrow m = 9m_{1} + 1;\]
\[\left( 9m_{1} + 1 \right)^{2} + 9m_{1} + 1 + 1 =\]
\[= 81m_{1}^{2} + 18m_{1} + 1 +\]
\[+ 9m_{1} + 2 =\]
\[= 81m_{1}^{2} + 27m_{1} + 3\ \vdots 3.\]
\[Получаем:\]
\[m^{3} - 1\ \vdots 27.\]
\[Что\ и\ требовалось\ доказать.\]