It is 81, because it has more than two factors (although they are all 3's). The other numbers are prime, because their only factors are 1 and themselves.
Both 41 and 47 are prime numbers.
All of them except for 31, 37, 41, 43 and 47 which are prime numbers
93 is composite.
prime: 31, 37, 41, 43, 47 composite: the others
93674731 = 19*1481*3329 and so it is a composite number.
If you mean: 53 81 41 47 and 31 then 81 is a composite number while all the rest are prime numbers
Both 41 and 47 are prime numbers.
All of them except for 31, 37, 41, 43 and 47 which are prime numbers
93 is composite.
Of these, 45 is the only composite number. All the others are prime.
prime: 31, 37, 41, 43, 47 composite: the others
All of them except for 31, 37, 41, 43 and 47 which are prime numbers.
All of them except for 31, 37, 41, 43 and 47 which are prime numbers.
93 = 3 x 31 31 47 67 are prime
93674731 = 19*1481*3329 and so it is a composite number.
31, 37, 41, 43, 47 are prime numbers from 30 to 50.
31, 47 and 103 are prime. The rest are composite.