RAR files are often used to distribute software or media. If you downloaded this from an untrusted source, it could contain malicious software. Always scan multi-part archives with updated antivirus software before extracting them [2].
Are you getting a specific when trying to open it? Do you have all 20 parts downloaded? 0001-0020.part3.rar
It seems you're asking about the file . This filename structure is a classic indicator of a multi-part archive created with WinRAR [1]. RAR files are often used to distribute software or media