Factors of 40
Factors of 40 are numbers that, when multiplied in pairs give the product as 40. There are 8 factors of 40, which are 1, 2, 4, 5, 8, 10, 20 and 40. Here, 40 is the biggest factor. The Prime Factors and Pair Factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40 and (1, 40), (2, 20), (4, 10) and (5, 8) respectively.
 Factors of 40: 1, 2, 4, 5, 8, 10, 20 and 40
 Negative Factors of 40: 1, 2, 4, 5, 8, 10, 20 and 40
 Prime Factors of 40: 2, 5
 Prime Factorization of 40: 2 × 2 × 2 × 5 = 2^{3} × 5
 Sum of Factors of 40: 90
1.  What Are the Factors of 40? 
2.  How to Calculate Factors of 40? 
3.  Factors of 40 by Prime Factorization 
4.  Factors of 40 in Pairs 
5.  FAQs on Factors of 40 
What are Factors of 40?
The number 40 is an even composite number. Since it is even, it will have 2 as its factor. To understand why it is composite, let's recall the definition of a composite number. A number is said to be composite if it has more than two factors. Consider the number 13. It has only two factors, 1 and 13 which means that it is prime. Now, let's take the case of 48. The factors of 48 are 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48. There are more than two factors of 14. Hence it is composite. Therefore factors of 40 are all the integers that 40 can be divided into which are 1, 2, 4, 8, 10, 20, 40.
How to Calculate the Factors of 40?
 Step 1: Let's begin calculating the factors of 40, starting with the smallest whole number, i.e., 1.
 Step 2: Divide 40 with this number. Is the remainder 0?
 Yes! So, we will get 40 ÷ 1 = 40, and the remainder is 0.
 Step 3: The next whole number is 2. Now divide 40 with this number. 40 ÷ 2 = 20
 Proceeding in a similar manner, we get 40 = 1× 40 = 2 × 20 = 4 ×10 = 5 × 8.
 Hence, the factors of 40 are 1, 2, 4, 5, 8, 10, 20, and 40.
Explore factors using illustrations and interactive examples.
 Factors of 36  The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36
 Factors of 24  The factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24
 Factors of 45  The factors of 45 are 1, 3, 5, 9, 15, 45
 Factors of 15  The factors of 15 are 1, 3, 5, 15
 Factors of 140  The factors of 140 are 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140
 Factors of 400  The factors of 400 are 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200, 400
Factors of 40 by Prime Factorization
Prime factorization means expressing a composite number as the product of its prime factors. To get the prime factorization of 40, we divide it by its smallest prime factor, which is 2, 40 ÷ 2 = 20. Now, 20 is divided by its smallest prime factor and the quotient is obtained. This process goes on till we get the quotient as 1.
The prime factorization of 40 is shown below:
Factors Pair Factor 1 × 40 = 40 (1,40) 2 × 20= 40 (2,20) 4 × 10 = 40 (4,10) 5 × 8 = 40 (5,8) 8 × 5 = 40 (8,5) 10 × 4 = 40 (10,4) 20 × 2 = 40 (20,2) 40 × 1 = 40 (40,1)
 Observe in the table above, after 5 × 8, the factors start repeating. So, it is enough to find factors till (5,8)
 If we consider negative integers, then both the numbers in the pair factors will be negative. We know that  ve ×  ve = +ve
 So, we can have factor pairs of 40 as (1,40) ; (2,20); (4,10); (5,8)
Challenging Questions:
 Are 0.4 and 100 factors of 40? Why do you think so?
 Are 5 and 8 factors of 40? Why do you think so?
Factors of 40 Solved Examples

Example 1: Peter and Andrew both have rectangular papers with dimensions as shown below.
The length and breadth of the first rectangular paper are 8 inches and 5 inches, and the length and breadth of the second rectangular paper are 10 inches and 4 inches. They place the two rectangles one over another. Since the two shapes do not overlap, Peter said that they don't have the same area. However, Andrew does not agree with him. Can you find out who is correct?
Solution: Area of a rectangle = length × breadth
For the first rectangle, Area = 8 × 5 = 40
For the second rectangle, Area = 10 × 4 = 40
Hence, the two rectangles have equal areas and Andrew is correct. 
Example 2: Jill has (4) as one of the factors of 40. How will she get the other factor?
Solution: 40 = Factor 1 × Factor 2, so we can say that 40 = (4) × Factor 2. Now, calculating for factor 2, Factor 2 = 40 ÷ (4) = (10).
Hence, the other factor is 10.

Example 3: Find the Least Common Multiple and Greatest Common Factor (GCF) of 40 and 36.
Solution:
The factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40 and factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36.
Therefore, the Least Common Multiple of 40 and 36 is 360 and the Greatest Common Factor (GCF) of 40 and 36 is 4.
FAQs on Factors of 40
What are the Factors of 40?
The factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40 and its negative factors are 1, 2, 4, 5, 8, 10, 20, 40.
What are the Prime Factors of 40?
The prime factors of 40 are 2, 5.
What is the Sum of the Factors of 40?
Sum of all factors of 40 = (2^{3 + 1}  1)/(2  1) × (5^{1 + 1}  1)/(5  1) = 90
What is the Greatest Common Factor of 40 and 28?
The factors of 40 and 28 are 1, 2, 4, 5, 8, 10, 20, 40 and 1, 2, 4, 7, 14, 28 respectively.
Common factors of 40 and 28 are [1, 2, 4].
Hence, the Greatest Common Factor of 40 and 28 is 4.
How Many Factors of 40 are also Factors of 30?
Since, the factors of 40 are 1, 2, 4, 5, 8, 10, 20, 40 and the factors of 30 are 1, 2, 3, 5, 6, 10, 15, 30.
Hence, [1, 2, 5, 10] are the common factors of 40 and 30.