# Why isn't 57 a prime number?

##### 3 Answers

#### Answer

#### Answer:

#### Explanation

#### Explanation:

#### Answer:

#### Explanation:

At first glance

after all,

Why not

If you add the digits of

This means that

The nearest multiples of

There are

These are

As it is a product of two primes and above the normal times tables, we will not often have come across

#### Answer

#### Answer:

#### Explanation

#### Explanation:

Describe your changes (optional) 200

#### Answer:

Prime numbers are only divisible by 1 and itself. So 57 is not a prime number (as it is divisible by 3).

#### Explanation:

We start with 57.

Sum the digits: 12.

Once more sum the digits: 3.

This means the original number is divisible by 3. (This holds for all numbers.)

Prime numbers are only divisible by 1 and itself. So 57 is not a prime number.

#### Answer

#### Answer:

#### Explanation

#### Explanation:

Describe your changes (optional) 200

#### Answer:

#### Explanation:

A prime number is one who does not have any factor other than one and itself.

Hence,

Describe your changes (optional) 200