# Is 81 Prime Number or Composite Number

Last Updated: April 27, 2024

## Is 81 a Prime Number?

### No: 81 is not a Prime Number.

Why No: 81 is not a prime number because it does not meet the prime criteria of having exactly two distinct positive divisors: 1 and itself. See Prime number checker

## Is 81 a Composite Number?

### Yes: 88 is a Composite Number.

Why Yes: 81 is a composite number because it has more than two distinct positive divisors. It is divisible by 1, 3, 9, 27, and itself (81).

## Problem Statements

Is 81 a prime number? No
Is 81 a composite number? Yes
Is 81 a perfect square? Yes
Factors of 81 1, 3, 9, 27, 81
Multiples of 81 81, 162, 243, 324, 405, 486, 567, 648, 729, 810
Cube Root of 81 4.327
Square of 81 6561
Square Root of 81 9
Is 81 a Perfect Cube? No
Is 81 an Irrational number No
Is 81 a Rational number Yes
Is 81 a Real number Yes
Is 81 an Integer Yes
Is 81 a Natural number Yes
Is 81 a Whole number Yes
Is 81 an Even or odd number Yes (81 is an odd number)
Is 81 an Ordinal number Yes
Is 81 a Complex number Yes (as all real numbers are also complex numbers)

## What are the factors of 81?

The factors of 81 are 1, 3, 9, 27, and 81. 81 is not a prime number because it is divisible by numbers other than 1 and itself, demonstrating it has more than two factors. This clarity confirms that it is a composite number, not a prime number.

## What Kind of Number is 81?

• 81: A Composite Number with Unique Divisors
• The Oddity of 81: Distinguishing It from Even Numbers
• 81’s Significance: Beyond Just a Number
• 81 as a Natural and Positive Integer
• 81 in Mathematical Dialogue: Composite Over Prime
• The Rationality and Wholeness of 81
• 81: An Integral Part of Mathematical Discussions.

## Nearest Prime Number of 81

The nearest prime numbers to 81 are 79 and 83. 79 is the closest prime number less than 81, and 83 is the closest prime number greater than 81.

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