The molar mass of Ag is 108 grams per mole.
So, divide the density of Ag which is 10.5 g/cm3 by 108 grams per mole and you will get 0.0972 moles per cubic centimeter.
Using Avogadro’s law where 1 mole of substance equals 6.023 x 10^23 atoms
0.0972 moles per cubic centimeter (6.023 x 10^23 atoms/mole) = 5.86 x 10^22 atoms Ag