For which of the following numbers is the sum of all its factors not equal to a square number?
Select one option, then click Submit.
3
22
40
66
70
Select an option, then submit.
Sign in or create an account to reveal answers, view the solution, and save your progress. Create a free account to unlock practice and keep track of your work.
Intermediate Mathematical Challenge 2013 (2013)
One puzzle per day. Cryptarithm, Magic Square, Summit. No sign-up required to play.
Play daily puzzle →Interactive problems and curated lessons—water pouring, magic squares, knight's tour, and more.
Browse library →See how you rank. Top solvers by problems solved correctly. Sign in to climb the ranks.
View leaderboard →Intermediate Mathematical Challenge 2013 (2013)