Concept 7 of 8Foundation
Watch on YouTubeVideoPerfect numbers & other special numbers
A perfect number equals the sum of its proper factors (all factors except itself).
- 6 = 1 + 2 + 3 ✓
- 28 = 1 + 2 + 4 + 7 + 14 ✓
- Next perfect numbers are 496 and 8128 — rare!
An abundant number: sum > n. Deficient: sum < n.
Example
Check if 12 is perfect: factors 1+2+3+4+6 = 16 > 12 → abundant.
💡 Tip:Perfect numbers are rare and beautiful — pop up in olympiads.
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5 questions to check what you just read.
0 / 5
- Q1.Is 6 a perfect number?
- Q2.Next perfect number after 6:
- Q3.Proper factors of 12 sum to:
- Q4.Proper factors of 8 sum to:
- Q5.A number whose proper factors sum LESS than itself is: