$${\begin {array} {l}n = \frac {10500 \frac {kg} {m^3}} {0,108 \frac {kg} {mol}} \, 6,02 \cdot 10^{23} \frac {1} {mol} \\ \approx 5,9 \cdot 10^{28} \frac {1} {m^3} \end {array}}$$