[CRGreathouse]

Originally Posted by paulunderwood

Is there a work-around?

Yes: you can use forvec like so:

forbigdiv(n, func)=
{
  my(f=factor(n));
  forvec(v=vector(#f~,i,[0,f[i,2]]),
    f[,2] = v~;
    func(factorback(f))
  );
}

which can be used like:

s=0; forbigdiv(183783600, d -> s += sigma(d)); s