291608esdlcdrsllbrnld: Mobi

It may be a unique identifier (GUID) used by a library management software like Calibre or a specific digital retailer’s backend database.

Import the file into a tool like Calibre. It will automatically read the internal metadata (title, author, and cover) regardless of the file's external name. 291608esdlcdrsllbrnld mobi

If you have this file on your device, you can try the following to see the real title: It may be a unique identifier (GUID) used