You can save your burner number to your contact. This can be useful as a way to keep track of your burner numbers.
In order to do so, go to the settings section of your burner by tapping the settings icon in the bottom right of the main screen.
From there, tap on the burner's number at the top of the screen to see an additional menu with options like "Copy" and "Memorize". Tap the right arrow and you'll see a "Save to contacts" option.