The visual brightness (apparent magnitude) of the sun is -26.7.
The apparent magnitude is a measure of a star’s brightness from the Earth.
It is a reverse logarithm scale such that the brightest object will have the lowest magnitude.
An increase of 1.0 in magnitude corresponds to a brightness ratio of 5√100.
For example, the apparent magnitude of sun and the full moon is -26.74 and -12.74 respectively.
Difference in magnitude => -12.74-(-26.74) =>14.
Therefore, the sun is approximately 398107 (= 100^(14/5)) times brighter than the moon.