On android we have two news, one bad and one good, the bad is that Android don't have a IP analyzer by default, only we can access the device IP going to settings/device info/status. But this don't have the router IP Address info. The good news is there is many free apps that allows us to do it, one we chose for this tutorial is WiFi Analyzer.
Once installed, open the app and will show all the AP availables, channels and its signal transmission power
To see your router IP Address click on 'menu' and then 'tools' and select 'LAN Neighbors'
And then you can access the router configuration using your favorite android web browser.