I would like to nominate the old spiritual "In Every Graveyard".
The relevant verse is:
Just behold that number
Just behold that number
Just behold that number
In every graveyard.
   
This is clearly meant to refer to EVERYONE who has ever died, so is unlikely to be beaten. There may of course be songs that refer to the fact that everyone is going to die in the future, which could be considered to refer to a larger number; but I think songs like that should be classed as hypothetical and should be disqualified.