How do you download it without signing up for utube and pay them?
I usually use a Firefox add-in called Video Download Helper but it saved this video without audio for some reason. So I went looking for the best recommended downloading software based on reviews and ended up getting this one:
https://www.4kdownload.com/products/product-videodownloader
It worked perfectly. You do have to install it on your PC but you give it the YouTube URL and it does the rest.