Factors of 645
Factors of 645 are numbers that, when multiplied in pairs give the product as 645. There are 8 factors of 645, which are 1, 3, 5, 15, 43, 129, 215, 645. Here, 645 is the biggest factor. The sum of all factors of 645 is 1056 and its factors in Pairs are (1, 645), (3, 215), (5, 129), (15, 43).
 All Factors of 645: 1, 3, 5, 15, 43, 129, 215 and 645
 Negative Factors of 645: 1, 3, 5, 15, 43, 129, 215 and 645
 Prime Factors of 645: 3, 5, 43
 Prime Factorization of 645: 3^{1} × 5^{1} × 43^{1}
 Sum of Factors of 645: 1056
1.  What Are the Factors of 645? 
2.  Factors of 645 by Prime Factorization 
3.  Factors of 645 in Pairs 
4.  FAQs on Factors of 645 
What are Factors of 645?
Factors of 645 are pairs of those numbers whose products result in 645. These factors are either prime numbers or composite numbers.
How to Find the Factors of 645?
To find the factors of 645, we will have to find the list of numbers that would divide 645 without leaving any remainder.
 645/3 = 215; therefore, 3 is a factor of 645 and 215 is also a factor of 645.
 645/43 = 15; therefore, 43 is a factor of 645 and 15 is also a factor of 645.
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Factors of 645 by Prime Factorization
 645 ÷ 3 = 215
Further dividing 215 by 3 gives a nonzero remainder. So we stop the process and continue dividing the number 215 by the next smallest prime factor. We stop ultimately if the next prime factor doesn't exist or when we can't divide any further.
So, the prime factorization of 645 can be written as 3^{1} × 5^{1} × 43^{1} where 3, 5, 43 are prime.
Factors of 645 in Pairs
Pair factors of 645 are the pairs of numbers that when multiplied give the product 645. The factors of 645 in pairs are:
 1 × 645 = (1, 645)
 3 × 215 = (3, 215)
 5 × 129 = (5, 129)
 15 × 43 = (15, 43)
Negative pair factors of 645 are:
 1 × 645 = (1, 645)
 3 × 215 = (3, 215)
 5 × 129 = (5, 129)
 15 × 43 = (15, 43)
NOTE: If (a, b) is a pair factor of a number then (b, a) is also a pair factor of that number.
Factors of 645 Solved Examples

Example 1: How many factors are there for 645?
Solution:
The factors of 645 are 1, 3, 5, 15, 43, 129, 215, 645. Therefore, 645 has 8 factors.

Example 2: Find the LCM and Greatest Common Factor (GCF) of 645 and 116.
Solution:
The factors of 645 are 1, 3, 5, 15, 43, 129, 215, 645 and factors of 116 are 1, 2, 4, 29, 58, 116.
Therefore, the LCM of 645 and 116 is 74820 and Greatest Common Factor (GCF) of 645 and 116 is 1. 
Example 3: Find if 1, 3, 15, 215 and 613 are factors of 645.
Solution:
When we divide 645 by 613 it leaves a remainder. Therefore, the number 613 is not a factor of 645. All numbers except 613 are factors of 645.

Example 4: Find the product of all the prime factors of 645.
Solution:
Since, the prime factors of 645 are 3, 5, 43. Therefore, the product of prime factors = 3 × 5 × 43 = 645.
FAQs on Factors of 645
What are the Factors of 645?
The factors of 645 are 1, 3, 5, 15, 43, 129, 215, 645 and its negative factors are 1, 3, 5, 15, 43, 129, 215, 645.
What is the Sum of Factors of 645?
Sum of all factors of 645 = (3^{1 + 1}  1)/(3  1) × (5^{1 + 1}  1)/(5  1) × (43^{1 + 1}  1)/(43  1) = 1056
What are Pair Factors of 645?
The pair factors of 645 are (1, 645), (3, 215), (5, 129), (15, 43).
What is the Greatest Common Factor of 645 and 33?
The factors of 645 and 33 are 1, 3, 5, 15, 43, 129, 215, 645 and 1, 3, 11, 33 respectively.
Common factors of 645 and 33 are [1, 3].
Hence, the Greatest Common Factor of 645 and 33 is 3.
How Many Factors of 645 are also Factors of 61?
Since, the factors of 645 are 1, 3, 5, 15, 43, 129, 215, 645 and factors of 61 are 1, 61. Hence, 645 and 61 have only one common factor which is 1. Therefore, 645 and 61 are coprime.
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