What is is 18 and 22 weird?

Based on commonly accepted definitions, the numbers 18 and 22 are not considered weird numbers.

Here's why:

• A weird number is a positive integer that is abundant (the sum of its proper divisors is greater than the number itself) but is not a semperfect number (it is not equal to the sum of some subset of its proper divisors).

• Let's examine 18:

  • Its proper divisors are 1, 2, 3, 6, and 9.
  • The sum of these divisors is 1 + 2 + 3 + 6 + 9 = 21. Since 21 > 18, 18 is an abundant number.
  • However, 18 is a semperfect number because 1 + 2 + 3 + 6 + 6 = 18 (using 6 twice). So, 18 is not weird.

• Let's examine 22:

  • Its proper divisors are 1, 2, 11.
  • The sum of these divisors is 1 + 2 + 11 = 14. Since 14 < 22, 22 is not even an abundant number in the first place.