This is a spin down D20, meaning if you turn the dice from one face to another, you can go down from 20 to 1 in consecutive order. It's not that obvious from the render and 3d model, but this one has a groove cut in so it's more obvious how to turn the dice to get the next number. But this means it probably wouldn't work as well as an actual dice.

Edit1: Deepened the groove a bit, it wasn't noticeable at small scale. Also added a version with slightly larger rounded font for easier printing.

Edit2: Added another font, this time using MuseoModerno. It's bolder than the previous font, with more horizontal lines and fewer sharp angles. Hopefully that makes clean-up even easier.