\[\left( \frac{2}{3}x^{2}y^{3} \right)^{3} \cdot \left( - 9x^{4} \right)^{2} =\]
\[= \left( \frac{2}{3} \right)^{3}x^{6}y^{9} \cdot ( - 9)^{2}x^{8} =\]
\[= \frac{8}{27} \cdot 81 \cdot x^{6 + 8}y^{9} = 24x^{14}y^{9}.\]