If a galaxy with a mass of 10⁴⁰ kg is acting as a gravitational lens at a distance of 1 million light-years, for a source 1.5 million light-years away, calculate the Einstein radius using the formula: where G is the gravitational constant, M is the mass of the lens, Dₛ is the distance to the source, and Dᵢ is the distance to the lens.