rotating images and/or text on pdf's

I have several pdf's that have half of the page upside down since the page was originally meant to be folded in half before reading; however, I would like to rotate the text and/or image so that it can be printed on a single page and read without having to fold the page. There are several pdf's in a single pdf (merged) to make the rotation faster. I have already done several myself so it is very easy work but tedious. The pdf's equal about 550 megabytes. so a fast internet connection is needed to download and upload. I use a program called nitro pdf and recommend you do the same.