Multiple choice general knowledge science & technology

What is a perfect number?

  1. A number such that the sum of its factors, excluding itself, is greater than itself

  2. A number such that its only divisors are 1 and itself

  3. A number such that the sum of its factors, excluding itself, equals itself

  4. A number such that it cannot be expressed as the ratio of two integers
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A perfect number is a positive integer equal to the sum of its proper divisors (excluding itself). The smallest perfect number is 6 (1+2+3=6). Option A describes an abundant number. Option B describes prime numbers. Option D describes irrational numbers. Only option C correctly defines perfect numbers, a concept dating back to Greek mathematics.

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