Yes, it is.
I don't use a tablet either - mainly because mine is truly ancient (it doesn't even have compatible drivers for pen pressure anymore) and pen is super big and pretty heavy. So I use mouse instead.
If you need some software, I can recommend looking for free analogues of Photoshop/Corel painter.
Krita, for example, is great. I didn't like SAI but a lot of people say that it's good. GIMP and Fire Alpaca are also a thing.