This is all up to the server package you order from the data center, the most common amount of IP's are 1,5,8,13,32 its likely you will have one or all of these amounts giving to you depmending on rules of use or the data centers TOS/AUP.

A server IP is a 4 prefix set of numbers giving to your machine such as this is the main IP then the additional IP's you are given run from the main IP.

The main IP can be shared if you wish but most hosting companies do not wish to disclose this information.