It may be a file from a peer-review portal where "753" is the submission or tracking number for a "Research Paper." Important Security Note
A very small file (a few KB) may be a script, while a larger file is more likely to contain a legitimate document or dataset. 753_RP.rar
The file appears to be a compressed archive, but it is not a widely recognized public academic article or standard citation format . It may be a file from a peer-review
Some organizations (like NASA or IEEE) use numeric identifiers for technical reports. " followed by a tracking number.
Many universities or internal corporate databases use "RP" as an abbreviation for "Research Project" or "Research Paper," followed by a tracking number.