If your inner page has link back to homepage then the number of content pages will have an influence with homepage pagerank and serp in one way or another. However, if you focusing too many backlink from inner page to homepage with a certain keyword, it may be considered as spam attempt from Google perspective and might cause a dropped in website ranking at last.
I have a site on every page of which there is a link to mainpage with the same anchor. The site is ranking great for this highly popular 4 000 000 pages keyword. So no penalties. In general, the amount of pages is not the definitive factor for assigning PR at all. But if those lots of pages will be filled with unique content - you will get your high PR, as the sun goes up from the east side.
huge number page means bots spend more time when crawling your site.. but it still depends on your site link structure.. to get most the use of it, try get your site more bots friendly..
I think the website page number doesn't matter that much. But what really matters is their depth. Try to make all the pages crawalable by the search engine spiders. Link them from the main category landing pages and the static sitemap page. Also, if you have all the pages interlinked then you gets the benefit for the Pagerank.