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![What are Perfect Numbers? - Examples, and Fact [with video] - Teachoo - Factors and Multiples](https://cdn.teachoo.com/391c1205-dceb-409d-8dc9-d4bf87035d4b/slide12.jpg)
Perfect Numbers
Last updated at July 8, 2025 by Teachoo
Factors and Multiples
Class 6 (Ganita Prakash & Old NCERT)
Chapter 5 Class 6 - Prime Time (Ganita Prakash)
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Factors and Multiples
- Common Multiples
- Common Factors
- Idli Vada Game
- Jumpy Jackpot
- Figure it out - Page 110, 111
- Prime Numbers
- Figure it out - Page 114, 115
- Co-prime numbers (and art)
- Prime Factorisation
- Uses of Prime Factorisation
- Divisibility Tests
- Figure it out - Page 125, 126
- Fun with numbers
- Teachoo Questions - MCQs
- Teachoo Questions - Mix
- Teachoo Questions - Assertion Reasoning
- Teachoo Questions - Case Based
Transcript
Perfect numbers If Sum of all factors is equal to twice the number, then number is called a perfect number For 6 Factors of 6 are 1, 2, 3, 6 Sum of factors = 1 + 2 + 3 + 6 = 12 Since 12 = 2 × 6 ∴ Sum of factors is equal to twice the number So, 6 is a perfect number For 28 Factors of 28 are 1, 2, 4, 7, 14, 28 Sum of factors = 1 + 2 + 4 + 7 + 14 + 28 = 56 Since 56 = 2 × 28 ∴ Sum of factors is equal to twice the number So, 28 is a perfect number For 10 Factors of 10 are 1, 2, 5, 10 Sum of factors = 1 + 2 + 5 + 10 = 18 Since 18 is not twice of 10 So, 10 is not a perfect number First 10 perfect numbers are 6 28 496 8128 33550336 8589869056 137438691328 2305843008139952128 2658455991569831744654692615953842176 191561942608236107294793378084303638130997321548169216
