How many atomic bombs does it take to launch a nuclear attack on Japan?

In the case of saturated bombing, the total area of Japan, including small islands, is 377,835 square kilometers. Then, take a neutron bomb with an equivalent of 65438+ 1 100 million tons, and the effective killing radius of a bomb =1.493885 *10000 (1effective killing area = pi * 32.18 *). You can bomb the whole of Japan without dead ends. I mean, effective lethality. However, I'm afraid the earth can't stand it.