Filenames that are strictly numeric are almost always . In the early days of file-sharing sites and video hubs, servers didn’t save files as "Funny_Cat_Video.mp4." Instead, they assigned a sequential ID to keep things organized.
While I can't "play" the file directly for you here, files in this specific numeric range from the mid-2000s typically fall into a few categories: 14047.flv
Sometimes the "Date Modified" or internal tags can tell you the original site of origin. Filenames that are strictly numeric are almost always
A cutscene or animation from a classic Flash game. 14047.flv