We are adding page numbers to our epubs according to the spec defined here. We would like to test this functionality though, are there any readers that support page numbers?
Take a look at Infinity Reader. https://play.google.com/store/apps/details?id=com.imeonsoft.infinity
It shows page numbers as well as audio, video and all ePub3 features. The reader comes with a free book, which contains youtube video.
Moreover, you can download a lot of free books.