A perfect number is a number that is equal to the sum of its proper factors. The first perfect number is 6. The proper factors of 6 are 1, 2, and 3. 1+2+3=6. The next perfect number is 28.
Saint Augustine (354-430) wrote:-
Six is a number perfect in itself, and not because G-d created all
things in six days; rather, the converse is true. G-d created all things
in six days because the number is perfect.
For more information on perfect numbers: Perfect_numbers