There are six zeros at the end of

3^{4} \times 4^{5} \times 5^{6}

We need to write the number in the form $a \times 10^{n}$ where $a$ is not a multiple of 10.

$3^{4} \times 4^{5} \times 5^{6} = 3^{4} \times 2^{10} \times 5^{6} = 3^{4} \times 2^{4} \times 2^{6} \times 5^{6} = 3^{4} \times 2^{4} \times 10^{6}$