Does having more pages on a website increase Google Pagerank and other search rank?

I second what the other guy said but it seems like he's assuming you know something I'm not sure you do. Page rank is based on how many site link to your site and and how much page rank those sites have. Its just one of the ways google decides how early to list your site for any given search along with how contextually relevant they think your site is to whatever someone is searching for. There's things you can do to help yourself out. For example make the text on your site uses can't see is relevant to what they can see. For example if you want people searching for widgets to find your content on widgets and your have a picture of a widget, name the graphic file widget.jpg. Name the page widget. Warning, don't get too tricky, google will punish you. Here's a good book on the subject.

Definitely not. Just take a closer look at results of 'site:' command for ecommerces, and compare their PRs with other ones that have much less sites indexed. As you will see, websites with 100k of indexed sites don't have a clear title to get higher PageRank... Google PageRank is based on number and quality of incoming links. Also, Google places importance on quality of content of website (more content, less outgoing links, never vice versa) In my humble opinion, as usually.

Have you verified your site and place a site map on Google admin center. That will help Google index your site. Alternatively, if its a commercial venture use Google Adword Marketing campaign @ http://www.geocities.com/lcming/adsense