Answer
$$9.06\times 10^{-11}.$$
Work Step by Step
We have
$$\left(\frac{ 1.3\times 10^4 }{(2.6\times 10^{-3})(5.1\times 10^8)}\right)^5=\left(\frac{ 1.3\times 10^4 }{13.26\times 10^5}\right)^5\\ =(0.098\times 10^{-1})^5 =0.00000906\times 10^{-5}\\ =9.06\times 10^{-11}.$$
