The string 21juakq87klo61 does not match widely indexed public documentation, which suggests it could mean a few different things:
What is the of the FLV file (e.g., are you trying to recover data from it, or solve a puzzle hidden inside)? 21juakq87klo61 flv
This query appears to be highly specific and potentially refers to a challenge, a specific malware sample, or a unique file identifier. The string 21juakq87klo61 does not match widely indexed