[math-fun] The Planck Power

c^5 / G = 3.6 * 10^52 watts. A black hole, in the final stage of its evaporation, lasting order one Planck time, would emit about this amount of power. Is it just an odd coincidence... that this amount of power, is roughly equal to the total luminosity of everything in the observable universe? (Actually, I think the universe currently is perhaps 10^5 times less powerful than the Planck power, but the universe was more powerful in the past.)