How to hide port no in url?

We have website http://xyz.abc.com:7778/. I would like to hide the port no. It should look like http://xyz.abc.com/
I have made change in apache conf file.
ProxyVia On
ProxyPass /xyz.abc.com:7778/ http://xyz.abc.com/
It could not resolve the problem. Any other method to resolve this?
Thanks