Square numbers have an odd number of factors. Other numbers have an even number of factors. The squares between 12 and 40 include 16, 25, and 36. If the number has only three factors, it must be the square of a Prime number, since two of the factors will be 1 and itself, so if there is only one more factor, this third number cannot have factors itself. This means the number must be 25, whose factors are 1, 5, and 25. Response: 24 has (at least) three factors - 1, 2, 3, 4, 6, 8, 12, and 24 .
28
66
It's a tie between 12 and 18. Each of them has 6 factors. Factors of 12: 1, 2, 3, 4, 6, and 12. Factors of 18: 1, 2, 3, 6, 9, and 18.
60, 72, 84, 90 and 96
The maximum number of different factors is 12 and there are 5 numbers in 1-100 which have 12 factors.
25 does.
25
9
25 it's factors are 1, 5,and 25. That's a number between 12 and 40 that has only 3 factors
25
The number that has only three factors between 12 and 40 is 16. The factors of 16 are 1, 2, 4, 8, and 16. Since 16 has only three distinct factors (1, 2, and 4), it meets the criteria specified.
25
12
28
Anywhere from 1 to an infinite number of factors. 1 has one factor. 9 has three factors. 84 has 12 factors. There is no limit.
25
Common factors are one and three.