Are there more stars than grains of sand on the Earth's beaches?

Carl Sagan is famous for saying there are more stars in our Universe than there are grains of sand on all the beaches on Earth. But is this actually possible? It's an awesome question — and a great excuse to do some math.

We know there are 100 to 400 billion stars in the Milky Way and more than 100 billion galaxies in the Universe — maybe as many as 500 billion. If you multiply stars by galaxies, at the low end, you get 10 billion billion stars, or 10 sextillion stars in the Universe. That's a 1 followed by 22 zeros. At the high end, it’s 200 sextillion.

Are there more stars than grains of sand on the Earth's beaches?