[tex]\displaystyle\\
16^4 \times 4^{10}\times 64^5=\\\\
=\Big(2^4\Big)^4 \times \Big(2^2\Big)^{10}\times \Big(2^6\Big)^5=\\\\
=2^{4\times4} \times2^{2\times10} \times2^{6\times5} =\\\\
=2^{16} \times2^{20} \times2^{30} = 2^{16+20+30} = \boxed{\bf 2^{66}}[/tex]