4,9,25. Any square with a Prime number as its root.
Okay, whoever said that a number can only have an even number of factors IS Wrong Take a prime number and square it. If you square a prime number, the number you get will only have 3 factors. For example, if I squared the number 3, I would get 9. 9 only has three factors: 9, 3, 1 Any prime number squared has Three factors.
No, only square numbers have an odd number of factors.
The largest two-digit number with exactly three factors is 99. A number has exactly three factors if it is the square of a prime number, specifically in the form ( p^2 ) where ( p ) is a prime. The only prime number whose square is a two-digit number is 7, since ( 7^2 = 49 ) and ( 11^2 = 121 ) exceeds two digits. Thus, 49 is the largest two-digit number with exactly three factors.
Factors can be listed as factor pairs. With square numbers, one of those pairs will be the same number twice. When written as a list, only one of them will be used, leaving an odd number of factors.
Factors come in pairs. It is only in the case of a square number that the two middle factors are equal and so are counted only once.