Q:

Write $1681$ using four $4$s

Write $1681$, using  $4$, four times only, and you can use any mathematical operation available within mathematics(except catenation or $4.4$ etc, it should be an operation), like factorial and cube root , $\sqrt{}$, greatest integer etc...
Example- writing $131096=4!+(\sqrt4\times {4^{4!!}})$ (yes for this example I first did the R.H.S!!)
I saw this question in a newspaper as a mathematical puzzle many years ago(in high school), and i solved it then, since then $1681$ is my favourite number, as took me $2$ days then to do it, but now i can't remember how i did it. Any help! I remember I had to use an operation which I was not much familiar with then.

A:

One way to do it is:
$$
\frac{(4 + 4)! + 4!}{4!}
$$

