What is a perfect number? A number is perfect if the sum of its proper factors is equal to the number.
To find the proper factors of a number, write down all numbers that divide the number with the exception of the number itself.
The proper factors of 18 are 1, 2, 3, 6, and 9
If the sum of the factors is equal to 18, then 18 is a perfect number.
1 + 2 + 3 + 6 + 9 = 6 + 6 + 9 = 12 + 9 = 21
Therefore, 18 is not pefect.
Another example: Find out if 496 is a perfect number
The proper factors of 496 are 1, 2, 4, 8, 16, 31, 62, 124, and 248
1 + 2 + 4 + 8 + 16 + 31 + 62 + 124 + 248 = 496
496 is perfect.
The first 10 perfect numbers are shown below. Notice that after the fourth one, they get pretty big faster.
6
28
496
8128
33550336
8589869056
137438691328
2305843008139952128
2658455991569831744654692615953842176
191561942608236107294793378084303638130997321548169216
May 21, 17 09:19 PM
Sharpen your math skills by grade here with crystal clear lessons
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
May 21, 17 09:19 PM
Sharpen your math skills by grade here with crystal clear lessons