Ensure it isn't a "double extension" file, such as 20613.mp4.exe . Windows often hides known file extensions, making a program look like a video. 3. Common "Numbered" Video Trends
The used to create it (e.g., Adobe Premiere, Handbrake). 20613mp4
If the file is safe but won't play, you can use to look at the metadata. This will tell you: The encoding date (when the video was made). Ensure it isn't a "double extension" file, such as 20613
Often, specific numbers become "codes" for certain types of internet content: 20613mp4