A free program for Android, by ColorFullDay.

All Router WiFi Passwords – Router Settings is a very simple application that allows you to access and manage your home WiFi network from your smartphone. The app is designed to be used by anyone with a smartphone and an Internet connection. It is a free application that does not require you to pay a penny to use it. The app can be used by anyone, even if they have no experience with WiFi or home networks. All you need to do is download the app, log in with your WiFi password, and you will be able to access your home network.