From the following URL, https://spacemath.gsfc.nasa.gov/weekly/RBSP9.pdf , we find the following text:

"At sea level, the average density of air molecules (oxygen and nitrogen) is 2.5x10^{25 }molecules/m^{3}."

One cubic centimeter would have one one-hundredth the dimensions of one cubic meter which means a volume of .01^{3} = 10^{-6} cubic meter. From that, we obtain that a volume of one cubic centimeter would give us 2.5 x 10^{25}/10^{6} molecules/cm^{3} = 2.5 x 10^{19} molecules/cm^{3}.

Each molecule of the two subject gases is made of two atoms. From this, we now say that the average atmospheric density is 2 x 2.5 x 10^{19} atoms/cm^{3}. which comes to 5 x 10^{19} atoms/cm^{3} which at one atmosphere of pressure, corresponds to 760 Torr.

We once had a lecturer at LICN who described a high vacuum system that was able to produce a pressure of 10^{-6} Torr, a level that was said to be state of the art. The atomic atmospheric density at that pressure would come to (10^{-6} / 760) x (5 x 10^{19}) = 6.58 x 10^{10} atoms per cm^{3}.

In Scientific American, June 2020, the article "A Planet Is Born" by Meredith A. MacGregor, on page 56, we read "The typical density of empty space is only one atom per cubic centimeter, ...".

From that ,we find pressure as (1 / (6.58 x 10^{10}) ) *10^{-6} Torr = 1.52 x 10^{-17} Torr.

To put this into a different perspective, we may write:

20 x log_{10} ((10^{-6} / (1.52 x 10^{-17})) = 20 x log_{10} (6.58 x 10^{10}) = 216 dB lower pressure level in space than in than the cited vacuum apparatus.

Mother Nature once again far outshines humanity's best achievement to date.