\frac{67, 3 M W}{139 \cdot 313600 m^{2}} = 1, 54 W / m^{2}

${\frac{67,3\, \mathrm{MW}}{139 \cdot 313600\, \mathrm{m^2}}= 1,54\, \mathrm{W/m^2}}$

Error