How many SARS-CoV-2 viruses in circulation at the moment? Mass?
Based on all species of viruses, Everyday you breathe in 100 million viruses. There can be 1mn+ viruses per ml of blood of patients. Covid-19 diameter = 125 nm.

Perhaps it's wrong, the maths would go something like this: 

1mn * 1000ml * 5liters * 400k patients = 2^12 - 2^13 sars2 viruses.

total volume of viruses =  2^13 viruses / 1^15 viruses per cm3 = 0.02 cm3

(10^7 nanometers per centimeter, 125nm diameter, gives, about 10^(5*3) viruses per cm3.)

Weight of all the Covid Sars 2 in the human population = a raindrop or a teaspoon of hydrocarbons/mayonnaise, probably less than a teacup.

Perhaps i am wrong, it's reasonable to think that the people with major symptoms contain about 1 ml of virus. 20k x 1ml = 20cm3