_-5172676927261.mp4 -

: Default recording tools on some mobile devices use similar numeric identifiers if a title isn't manually assigned.

The naming convention consisting of an underscore, a long string of numbers (often a timestamp or unique ID), and the .mp4 extension is common to several platforms: _-5172676927261.mp4

: Third-party downloaders for TikTok or Instagram often generate these random strings to avoid file name conflicts on your device. Technical Overview of .MP4 : Default recording tools on some mobile devices

The .mp4 extension (MPEG-4 Part 14) is a universal . MP4 files explained: How to open and use - Adobe _-5172676927261.mp4

: These apps often rename media files with numeric strings to keep them unique within their internal databases.