I had honestly never heard this statistic before, and it’s pretty amazing how well they fit together. In order of their distance from the Sun, they are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. This means that 30 Earth-sized planets could fit between Earth and Moon. The moon is an average of 238,855 miles (384,400 kilometers) away.
further 3,500 km is required to squeeze Neptune (5,900 km to include Pluto). If you divide the volume of the sun by the volume of the earth, you get that approximately 1.3 million earths fit in the sun.