Router IP Address on Mobile Devices
1) Press home button
2) Go to Settings.
3) Press on Wi-Fi
4) Select Wi-Fi network you're connected too.
5) Your router IP address will be in Router row. You can also see your current IP address in IP Address row.
Unix and Linux
Open a Terminal. One way to do it is to open Applications > Utilities > Terminal in Finder.
In terminal type the following command:
ip route | grep default
The output of this will look like the following:
joe$ ip route | grep default
default via 192.168.O.1 dev eth0 proto static
In this example, again, 192.168.0.1 is your default gateway (router) IP address.
Unfortunately as of now there is no way to find out router IP address on Android device in Settings interface. So you either have to use a special app for that or device with another OS.