$ sudo apt-get remove electrum 

Uninstall electrum including dependent package

If you would like to remove electrum and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove electrum 

Use Purging electrum

If you use with purge options to electrum package all the configuration and dependent packages will be removed.

$ sudo apt-get purge electrum 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove electrum 

See Also,