25
97 has two factors.
The number one has one factor. Prime numbers have two.
63? But it has more than two one-digit factors.
63
A two-digit number with exactly 7 factors must be of the form ( p^6 ), where ( p ) is a prime number, because the number of factors of ( n = p^e ) is ( e + 1 ). The only prime number that, when raised to the sixth power, results in a two-digit number is 2, since ( 2^6 = 64 ). Therefore, 64 is the only two-digit number that has exactly 7 factors.
24
36
It is 1 which has only one factor followd by any of the prime numbers which have only two factors
63.
The two-digit factors of 100 and 1000 are all composite.
101 is the first three-digit prime number.
Both 10 and 20 are two-digit numbers that are factors of 20.