The brightness of the Sun is measured in several different ways. For astronomers we use the value of 3.826 x 10^33 ergs/second or 328.6 trillion trillion watts as the total luminosity or power output of the Sun. At the distance of the earth, this corresponds to an energy flux of 62.84 billion ergs per second per square centimeter per second or 6284 watts per square centimeter. The total candle power of the Sun is 2.84 x 10^27 and its brightness at the Earth in terms of units called lux is 127000.
If the Sun were seen as a star from a distance of 10 parsecs, it would appear as a G-type star of apparent magnitude of about +5.0.