The number (1536) often refers to the vertical resolution (e.g., 1536p) or a specific archive index number. If it refers to resolution, this is a high-definition format exceeding standard 1080p.
If you are organizing this file in a library (like Plex or Kodi), you might use a description similar to this: Girls Forever (1536) mp4
To provide the most useful text, I have categorized the potential needs based on how this file is typically handled: The number (1536) often refers to the vertical resolution (e