SecondOnTheLock

Note: This app can not be used only up to Android7.1.1.

You can display seconds on the lock screen.
The displayed second can be brought to any position you like.
The color, size and size can be changed.
By the way, you can also display hours and minutes in addition to seconds.

In order to make it hard for this app terminated abnormally, this displays notification. (If your OS is Android4.4 or higher, you can block this notification.)