Expression for an electric field is given by $\overrightarrow{\mathrm{E}}=4000 x^{2} \hat{i} \frac{\mathrm{V}}{\mathrm{m}}$. The electric flux through the cube of side $20 \mathrm{~cm}$ when placed in electric field (as shown in the figure) is __________ $\mathrm{V} \mathrm{~cm}$.