Calculate work done to remove a electron at the above position from nucleus to infinity
Back in my school days, I have learnt this definition of potential.

"Potential at a point in electric field is defined as the amount of work to be done on unit positive charge to bring it from infinity to that point, without accelaration." Or you can also think like - it is the amount of work to be done on an electron to move it from that point to infinity. 

So in your case, the answer is nothing but the potential at the point, where the electron is currently now. if R is the distance to electron from nuclues and E is the electric field at that point. Then: $$V = E.R$$