The default ONVIF port for 2-series Hikvision cameras is 80.
The very good Windows open-source tool 'ONVIF Device Manager' from sourceforge.net will tell you lots about the camera that you won't find in other sources.
The 'ONVIF port' is shown in the URI at the bottom of the 'Identification' page. If there is no ':<port number>' in the URI, it's 80.
The 'RTSP string' is shown at the bottom of the 'Live Video' page.