All IP addresses are routable; as long as you have two unicast IP addresses that are on different IP networks (which is where the subnet mask comes in), then you can make a router route between them. (I carefully said 'unicast' because multicasts can be a little different but that's a digression). Having said that, there are a few IP address ranges that are not routable across the intenet - not because those addresses are some how not routable, but because by common agreement it was considered desirable to have some 'private' IP address ranges that you can use internally without fear of them being accessible to the world. If you're using your own private isolated network however you can route between these private addresses without any problem
