A perfect number is one that is the sum of its factors, excluding itself. The 1st perfect number is 6 because 6 = 1 + 2 + 3.
![A perfect number is one that is the sum of its factors, excluding itself. The 1st perfect number is 6 because 6 = 1 + 2 + 3.](http://www.huamaodashu.com/wp-content/themes/zimeiti-2/thumb.php?src=http://www.huamaodashu.com/wp-content/themes/zimeiti-2/assets/img/default.png&w=280&h=180)
A perfect number is one that is the sum of its factors, excluding itself. The 1st perfect number is 6 because 6 = 1 + 2 + 3.