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Prime factors of numbers from 1 to 100. Learn how to find and calculate factor trees of a number. All prime factors of 1-100 list. Prime factoring calculator.

- Prime factors of 1 are:

1 - Prime factors of 2 are:

1 *2 - Prime factors of 3 are:

1 *3 - Prime factors of 4 are:

2 - Prime factors of 5 are:

1 *5 - Prime factors of 6 are:

2, 3 - Prime factors of 7 are:

1 *7 - Prime factors of 8 are:

2 - Prime factors of 9 are:

3 - Prime factors of 10 are:

2, 5 - Prime factors of 11 are:

1 *11 - Prime factors of 12 are:

2, 3 - Prime factors of 13 are:

1 *13 - Prime factors of 14 are:

2, 7 - Prime factors of 15 are:

3, 5 - Prime factors of 16 are:

2 - Prime factors of 17 are:

1 *17 - Prime factors of 18 are:

2, 3 - Prime factors of 19 are:

1 *19 - Prime factors of 20 are:

2, 5 - Prime factors of 21 are:

3, 7 - Prime factors of 22 are:

2, 11 - Prime factors of 23 are:

1 *23 - Prime factors of 24 are:

2, 3 - Prime factors of 25 are:

5 - Prime factors of 26 are:

2, 13 - Prime factors of 27 are:

3 - Prime factors of 28 are:

2, 7 - Prime factors of 29 are:

1 *29 - Prime factors of 30 are:

2, 3, 5 - Prime factors of 31 are:

1 *31 - Prime factors of 32 are:

2 - Prime factors of 33 are:

3, 11 - Prime factors of 34 are:

2, 17 - Prime factors of 35 are:

5, 7 - Prime factors of 36 are:

2, 3 - Prime factors of 37 are:

1 *37 - Prime factors of 38 are:

2, 19 - Prime factors of 39 are:

3, 13 - Prime factors of 40 are:

2, 5 - Prime factors of 41 are:

1 *41 - Prime factors of 42 are:

2, 3, 7 - Prime factors of 43 are:

1 *43 - Prime factors of 44 are:

2, 11 - Prime factors of 45 are:

3, 5 - Prime factors of 46 are:

2, 23 - Prime factors of 47 are:

1 *47 - Prime factors of 48 are:

2, 3 - Prime factors of 49 are:

7 - Prime factors of 50 are:

2, 5 - Prime factors of 51 are:

3, 17 - Prime factors of 52 are:

2, 13 - Prime factors of 53 are:

1 *53 - Prime factors of 54 are:

2, 3 - Prime factors of 55 are:

5, 11 - Prime factors of 56 are:

2, 7 - Prime factors of 57 are:

3, 19 - Prime factors of 58 are:

2, 29 - Prime factors of 59 are:

1 *59 - Prime factors of 60 are:

2, 3, 5 - Prime factors of 61 are:

1 *61 - Prime factors of 62 are:

2, 31 - Prime factors of 63 are:

3, 7 - Prime factors of 64 are:

2 - Prime factors of 65 are:

5, 13 - Prime factors of 66 are:

2, 3, 11 - Prime factors of 67 are:

1 *67 - Prime factors of 68 are:

2, 17 - Prime factors of 69 are:

3, 23 - Prime factors of 70 are:

2, 5, 7 - Prime factors of 71 are:

1 *71 - Prime factors of 72 are:

2, 3 - Prime factors of 73 are:

1 *73 - Prime factors of 74 are:

2, 37 - Prime factors of 75 are:

3, 5 - Prime factors of 76 are:

2, 19 - Prime factors of 77 are:

7, 11 - Prime factors of 78 are:

2, 3, 13 - Prime factors of 79 are:

1 *79 - Prime factors of 80 are:

2, 5 - Prime factors of 81 are:

3 - Prime factors of 82 are:

2, 41 - Prime factors of 83 are:

1 *83 - Prime factors of 84 are:

2, 3, 7 - Prime factors of 85 are:

5, 17 - Prime factors of 86 are:

2, 43 - Prime factors of 87 are:

3, 29 - Prime factors of 88 are:

2, 11 - Prime factors of 89 are:

1 *89 - Prime factors of 90 are:

2, 3, 5 - Prime factors of 91 are:

7, 13 - Prime factors of 92 are:

2, 23 - Prime factors of 93 are:

3, 31 - Prime factors of 94 are:

2, 47 - Prime factors of 95 are:

5, 19 - Prime factors of 96 are:

2, 3 - Prime factors of 97 are:

1 *97 - Prime factors of 98 are:

2, 7 - Prime factors of 99 are:

3, 11 - Prime factors of 100 are:

2, 5

We arrived at our answers for prime factors by using the factor tree. However we could have also used upside-down division to get the factorization primes. There are more that one method to factorize a number.

Knowing these divisibility rules will help you find prime factors faster.

**Rule 1:** If the last digit of a number is 0, 2, 4, 6 or 8 then it is an even number. All even numbers are divisible by 2 and 2 is a prime factor.

**Rule 2:** If the sum of digits of a number is divisible by 3 then the number is also divisible by 3 and 3 is a prime factor(example: the digits of 12 are 1 and 2 so 1+2=3 and 3 is divisible by 3, meaning that 12 is divisible by 3). The same logic works also for number 9.

**Rule 3:** If the last two digits of a number are 00 then this number is divisible by 4(example: we know that 124=100-24 and 100 has two zeros in the end making it divisible with 4. We also know that 4 is divisible with 24). In order to use this rule to it's fullest it is best to know multiples of 4.

**Rule 4:** If the last digit of a number is 0 or 5 then 5 it is divisible by 5 and 5 is a prime factor.

**Rule 5:** All numbers that are divisible by both 2 and 3 are also divisible by 6.

All numbers that are only divisible by one and itself are called prime factors in mathematics. A prime factor is a number that has only two factors(one and itself).