Individual papers do not have an "impact factor". Journal impact factor is, as the name states, a journal-level metric. A brief read of: https://researchguides.uic.edu/if/impact and https://en.wikipedia.org/wiki/Impact_factor should help explain some particulars of how this measurement is calculated, interpreted and (mis)used.

Perhaps you are thinking of Citation Impact, which is still an author-level metric, not paper-level: https://en.wikipedia.org/wiki/Citation_impact.