What is the square root of the earths equator divided by the mass it's humen population?

It depends on your unit of measure

The Earth's equator is 24,901.55 miles or 40,075.16 km

The Earth's population is 6,973,738,433 (according to the World Bank)

The human population's mass has to be averaged - 120-140 lbs / 54-64 kg for females and 168-183 lbs / 76-83 kg for males

So, pick your units of measurement for the equator, and divide away!