Without more context, it is impossible to determine the exact contents of this specific file, as "22421.rar" is a generic naming convention that could be used for anything from driver updates to game mods or personal documents.
: This is a proprietary archive file format (Roshal Archive) used for data compression and error recovery. To open it, you typically need software like WinRAR or 7-Zip . 22421.rar
Do you have about where you found this file name or what it is supposed to contain? Without more context, it is impossible to determine