Factors of 81 | Factor Pairs, Prime Factorization & Divisors

📊 Total Factors: 5
🔢 Prime Factors: 3
✅ Number Type: Composite Number

What Are the Factors of 81?

The factors of 81 are 1, 3, 9, 27, 81. A factor is a whole number that divides 81 exactly without leaving a remainder. These factors can be used to simplify fractions, solve math problems, and understand number relationships.

How to Find the Factors of 81

To find the factors of 81, divide the number by whole numbers starting from 1. If the result is a whole number with no remainder, that divisor is a factor.

81 ÷ 1 = 81
81 ÷ 3 = 27
81 ÷ 9 = 9
81 ÷ 27 = 3
81 ÷ 81 = 1

Is 81 Divisible by Other Numbers?

A number is divisible by another number if the division leaves no remainder.

❌ 81 is not divisible by 2
✅ 81 is divisible by 3
❌ 81 is not divisible by 4
❌ 81 is not divisible by 5
❌ 81 is not divisible by 6
❌ 81 is not divisible by 7
❌ 81 is not divisible by 8
✅ 81 is divisible by 9
❌ 81 is not divisible by 10

Real-Life Uses of Factors of 81

Factors of 81 are useful in mathematics, grouping objects, simplifying fractions, finding dimensions of rectangles, and solving division problems. Understanding factors helps students build a strong foundation in arithmetic and number theory.

All Factors of 81

1, 3, 9, 27, 81

Factor Pairs of 81

• 1 × 81
• 3 × 27
• 9 × 9

Prime Factorization of 81

81 = 3 × 3 × 3 × 3

Worked Example: Finding Factors of 81

Step 1: Start testing numbers from 1 up to 81.

Step 2: Check which numbers divide 81 without leaving a remainder.

Step 3: The successful divisions are:

81 ÷ 1 = 81 (No remainder)
81 ÷ 3 = 27 (No remainder)
81 ÷ 9 = 9 (No remainder)
81 ÷ 27 = 3 (No remainder)
81 ÷ 81 = 1 (No remainder)

Answer: Therefore, the factors of 81 are 1, 3, 9, 27, 81.

Number Facts Table

Property	Value
Number	81
Total Factors	5
Largest Factor	81
Smallest Factor	1
Prime Factors	3
Even / Odd	Odd
Prime / Composite	Composite
Perfect Square	Yes
Perfect Cube	No

Properties of 81

Even or Odd: Odd Number

Prime or Composite: Composite Number

Perfect Square: Yes

Perfect Cube: No

Unique Prime Factors: 3

Interesting Facts About 81

• 81 is a composite number because it has more than two factors.
• 81 is an odd number.
• 81 is a perfect square number.
• The prime factorization of 81 is 3 × 3 × 3 × 3.
• 81 has 5 total factors.

Is 81 Prime or Composite?

81 is a composite number because it has 5 factors.

Related Factors Pages

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Factors of 79
Factors of 80
Factors of 82
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Frequently Asked Questions

What are the factors of 81?
1, 3, 9, 27, 81

How many factors does 81 have?
5

Is 81 a prime number?
No

What is the largest factor of 81?
81

What is the smallest factor of 81?
1

What are the prime factors of 81?
3

Is 81 even or odd?
Odd

What is the factor pair of 81?
1 × 81, 3 × 27, 9 × 9