It's not even close.
So let's do some simple math. A sand grain is defined as having a range of sizes, but 1mm diameter is typical. So for simplicity let's use that size.
The earth has an average radius of 6371km. This gives the earth a surface area of 1.28 times 10^14 square millimeters of surface area.
There are 7 times 10^22 stars. Divide this by the surface area of the earth and we learn how deep the sand across the entire earth would have to be to equal the number of stars.
The depth is 550km.
So it seems reasonable to conclude that there are more stars than there are grains of sands on all the beaches.
I'm having troubles following your math.
Earth: 6371km radius.
Surface area of a sphere: 4πr2
That gives us a surface area of:
= 5.1 x 108
in a m2
in a km2
So that gives us 1012
in a km2
So we get the surface area of the earth being about 5.1 x 1020
So, the difference between the number of stars and the number of square mm on the planet surface is only a factor of 102
(assuming the accuracy of all the estimates).
or, about 100mm, or about a shell 10cm thick.
So, the question is how much of the earth is covered by sand.
Component of dirt
I think you would find out that you would have more than adequate sand to cover the earth several times over with 10cm of sand.
(Oh, it looks like piktor67 was on the same track).