6562, 63 \cdot 10^{6} m^{2} \cdot 0, 5 W / m^{2} = 1, 64 G W

${6562,63 \cdot 10^6\, \mathrm{m^2}\cdot 0,5\, \mathrm{W/m^2} = 1,64\, \mathrm{GW}}$

Error