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Written by: Super User

Category: About us

Published: 06 January 2021

Question :- What is a Prime Number?

Answer:- These are whole numbers that are only divisible by 1 and by the number itself.

e.g. 11 = Divisible by 1 & 11

e.g. 31 = Divisible by 1 & 31

Non-prime numbers can be divided by two or more numbers.

e.g. 9 = Divisible by 1, 3 & 9

Prime Factors

This is prime numbers that are multiplied together give arrive at the number being considered.

e.g. The prime factors of 171 are 3, 3, 19

So 171 = 3 x 3 x 19

To find the Prime Factors of an odd number like 171

1) Look up the prime factor in the table below for 171 which is 3.

2) Divide 171 by 3 to give 57.

3) Look up 57 in the table below the smallest factor is 3 again.

4) Divide 57 by 3 to give 19.

5) Look up 19 in the table below the smallest factor is a P which means its a prime number itself.

To find the Prime Factors of an even number like 60

1) The smallest prime factor for an even is 2.

2) Divide 60 by 2 to give 30.

3) Divide 30 by 2 to give 15.

4) Look up 15 in the table below the smallest factor is 3 again.

5) Divide 15 by 3 to give 3.

6) Look up 3 in the table below the smallest factor is a P which means its a prime number itself.

Odd Prime Numbers & smallest factor lookup table

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