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Factors of 85
Factors of 85 are the numbers which when multiplied in pairs give the product as 85. Did you know that the number 85 is the length of the hypotenuse of four Pythagorean triangles? In this lesson, we will calculate the factors of 85, prime factors of 85, and factors of 85 in pairs along with solved examples for a better understanding.
 Factors of 85: 1, 5, 17 and 85
 Prime Factorization of 85: 85 = 5 × 17
What are the Factors of 85?
Factors of a given number are the numbers that divide the given number exactly without any remainder i.e. the remainder is 0. Following are the factors of 85 are 1, 5, 17 and 85. On adding its factors which are proper divisors, we get 1+5+17= 23 < 85 The sum of the proper divisors of 85 is less than 85 So, 85 is known as a deficient number.
How to Calculate the Factors of 85?
Various methods like prime factorization and the division method can be used to calculate the factors of 85. In prime factorization, we express 85 as a product of its prime factors and in the division method, we look for numbers that divide 85 without a remainder.
Important Notes:
 The factors of 85 are 1, 5, 17 and 85
 As 85 is strictly greater than the sum of its proper divisors, it is called a deficient number
 The smallest factor of a number is 1 and the greatest factor of a number would be the number itself
Hence, the factors of 85 are 1, 5, 17 and 85.
Explore factors using illustrations and interactive examples
 Factors of 75  The factors of 75 are 1, 3, 5, 15, 25 and 75
 Factors of 54  The factors of 54 are 1, 2, 3, 6, 9, 18, 27, 54
 Factors of 80  The factors of 80 are 1, 2, 4, 5, 8, 10, 16, 20, 40, 80
 Factors of 45  The factors of 168 are 1, 3, 5, 9, 15, 45
 Factors of 175  The factors of 175 are 1, 5, 7, 25, 35, 175
 Factors of 84  The factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
Prime factorization means expressing a number in terms of the product of its prime factors. We can do use the division method or factor tree to do this.
1. Prime Factorization by Division
The number 85 is divided by the smallest prime number which divides 85 exactly, i.e. it leaves a remainder 0. The quotient is then divided by the smallest or second smallest prime number and the process continues till the quotient becomes indivisible. Since 85 is an odd number, it will not be divisible by 2 and its multiples. Now, sum of digits of 85 = 8 + 5 = 13 which is not divisible by 3. So, 85 is not divisible by 3 as well. Since the last digit is 5, 85 is divisible by 5
85 ÷ 5=17
Now, 17 is again a prime number and hence can't be further divided. Prime factorization of 85 = 5 × 17
2. Prime Factorization by Factor Tree
The other way of prime factorization as taking 85 as the root, we create branches by dividing it by prime numbers. This method is similar to the above division method. The difference lies in presenting the factorization. The composite numbers will have branches as they are further divisible. We continue making branches till we are left with only prime numbers. Now that we have done the prime factorization of 85, we can multiply them and get the other factors. Can you try and find out if all the factors are covered or not? And as you might have already guessed it, for prime numbers, there are no other factors.
Factors of 85 in Pairs
The factor pairs of a number are the two numbers which, when multiplied, give the required number.
For example 10 × 9 = 90 and 5 ×18 = 90
So, (10,9) and (5,18) are pair factors of 90.
Considering the number 85, we have:
 1 × 85=85
 5 × 17=85
So, the pair factors of 85 are (1,85) and (5,17).
The product of two negative numbers is positive i.e. (ve) × (ve) = (+ve).
So, (1,85), (5,17) are also factor pairs of 85.
Challenging Questions:
 Do the numbers 85 and 0.85 have a common factor?
 Is there a natural number n, such that 85^{n} will end with digit 0? How will you justify your answer?
Factors of 85 Solved Examples

Example 1: Ryan's teacher told him that (5) is one of the factors of 85. Can you help him find the other factor?
Solution:
Since, (5 ) is one the factor of 85, we will divide 85 by (5) to get the other factor.
The other factor is 85 ÷ (5) = 17Hence, 17 is the other factor.

Example 2: Tom has 85 units of cup sets and he wants to pack them in the cartons such that these units are evenly distributed. There are three sizes of cartons available to him. The first type has a capacity of 5 units, the second, a capacity of 13 units, and the third, a capacity of 17 units. Which type of carton he will choose so that there is no unit left and minimum cartons are required?
Solution:
First condition: To find the type of carton such that after packing no unit is left, we need to find the factors of 85.
Here 5 and 17 are factors of 85, but 13 is not.
Second condition: Minimum cartons are required. Let's divide 85 by each of the factors 5 and 17 and decide in which case minimum cartons are required.85 ÷ 5 = 17 and 85 ÷ 17 = 5
So, when he takes a carton of capacity 17 units he requires only 5 cartons whereas if he takes a carton of capacity 5 units he would require 17 cartons.
Hence, Tom will choose a carton which has a capacity of 17 units.
FAQs on Factors of 85
What are the factors of 85?
The factors of 85 are 1, 5, 17, and 85.
What are the common factors of 85 and 145?
The factors of 85 are 1, 5, 17, and 85.
The factors of 145 are 1, 5, 29, 145.
So, The common factors are 1 and 5.
What are the prime factors of 85?
The prime factors of 85 are 5 and 17
What are the common factors of 51 and 85?
The factors of 85 are 1, 5, 17, and 85.
The factors of 51 are 1, 3, 17, and 51.
So, The common factors are 1 and 17.
What are the common factors of 85 and 115?
The factors of 85 are 1, 5, 17, and 85
The factors of 115 are 1, 5, 23, 115
Hence the common factors are 1, and 5
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