Catalytic converters are used in automobiles to convert harmful gaseous substances in the exhaust to more benign substances, for example, carbon monoxide to carbon dioxide. Beads used in these converters have extremely large surface areas. For instance, a single 3.0-mm porous bead can have a surface area of 1.0 × 10⁶ cm². If a car has two catalytic converters, each with 5.0 × 10³ beads, calculate the surface area of the two catalytic converters in km².