Adding a 'background' to page numbering

Hi,

I have a large document which includes multiple PDFs that have been imported into the appendices. 

I want to turn page numbering on so all the pages are numbered, which is easy enough of course.

The problem I have is that some of the pages (in the appendices) follow totally different formats or may have graphics and text where the page numbering is and therefore you are unable to see the page numbering on these pages.

Is it possible to format the page numbering in a way so that it always shows up - perhaps say a white box so it appears on top of other page elements?

Many thanks.

I'm using Acrobat XI.