Why isn't 57 a prime number?

Question

Why isn't 57 a prime number?

Answer 1

becuase they forgot to list it as a prime bunber back in old days

Answer 2

Because it has factors. 3 and 19

Answer 3

Because you can divide it by 1, 57 and...3

Add up the integers 5 + 7 = 12 and again 1 + 2 = 3 so it's divisible by three!

Divide by three and you get 19 which is another factor!

Hope that helps!

Answer 4

Add the digits :

5 + 7 = 12, which is divisible by 3.  

That is a quick and dirty check that it is a multiple of 3, and as mentioned before, 19 x 3 = 57.

Answer 5

its divisible by 3 and 19

Answer 6

Prime numbers are only divisible by 1 and the number itself. 57 is divisible by 3 and 19 therefore it is not prime

Answer 7

57 is NOT prime because it has factors other than one and itself.  Other factors of 57 are 3 and 19.

Answer 8

No,57/19=3, and 3X19=57.

Answer 9

it fits into none of the timetables exactly...

it cannot be divided by any whole number to give a whole number...

therefore it is a prime number...

Answer 10

57 is not a prime number because

3x19 = 57

a prime doesnt hav factors

Answer 11

Because it has factors other then 1 and the number itself which is 19 and 3

Answer 12

Because a prime number is one that's only divisible by itself and one. 57 does not follow this rule, as 3x19=57.

Answer 13

because it isn't.  It never will be. It has factors 1,3,19

a prime, say N,  has factors 1 and N only

eg: 2, 3, 5, 7.......37, 41,... etc

Answer 14

Cuz 19x3=57

Answer 15

No 57 is not a prime number because it can be divided by 1, 3 and 57.

A prime number is a number that can be divided by 1 and the number itself. So that is why 57 is not a prime number. Just because 5 and 7 are prime numbers that doesn't make them a prime number together.

Answer 16

it's so because it has four factors

1,3,19,57

and a no is said to be prime when it has only 2 factors i.e. 1 and the no itself.

Answer 17

Prime number definition is that a number can only divide itself and one like 2 can divide by 1 and 2,itself so it is a prime number. So, the number 57 has a factors of 1,3,19 and 57.then it is a prime number.

Answer 18

Because 3 goes into it evenly... 19 times to be exact.

Answer 19

19x3

Answer 20

because you can divide it by 19.

57 / 19 = 3

a prime number is only divisible by itself.

Answer 21

Factors of 57:

1 , 3 , 19 , 57

(it has more than 2 factors, so it is a complex number.)

Answer 22

19 X 3....................................

Answer 23

3 x 19 = 57