How many Jews were slaves in Egypt?

The Gemara in Sanhedrin (111) makes a startling statement about the numbers of Jews in Egypt. It says only 2 out of every 600,000 made it out, all the rest died. When you do the math (600,000 actually came out) it comes out to an unfamothable 180,000,000,000 (180 billion) Jews were slaves in Egypt. Given that the world population in 2017 is only 7.6 billion and the population only rreached 1 billion in 1804 this number is so ridiculous it is silly.