\[- 1\frac{2}{3}a^{3}b^{6} \cdot \left( - \frac{3}{5}a^{2}b \right)^{3} =\]
\[= - \frac{5}{3}a^{3}b^{6} \cdot \left( - \frac{27}{125} \right)a^{6}b^{3} =\]
\[= \frac{9}{25}a^{9}b^{9}\]