Relatively Prime Calculator

Check if numbers are coprime (relatively prime) by analyzing their greatest common divisor

Calculate Relatively Prime Numbers

Example Calculations

Example 1: Coprime Numbers

Numbers: 14 and 15

14 = 2 × 7

15 = 3 × 5

Common factors: None (only 1)

GCD: 1

Result: 14 and 15 are relatively prime ✓

Example 2: Not Coprime

Numbers: 18 and 27

18 = 2 × 3 × 3

27 = 3 × 3 × 3

Common factors: 3

GCD: 9

Result: 18 and 27 are NOT relatively prime ✗

Example 3: Set Analysis

Set: 21

GCD(4, 6, 21) = 1 → Setwise coprime ✓

GCD(4, 6) = 2 → Not pairwise coprime ✗

Result: Setwise coprime but not pairwise coprime

Quick Facts

Two numbers are coprime if their GCD is 1

Coprime numbers don't need to be prime themselves

The number 1 is coprime with every positive integer

Two even numbers can never be coprime

How to Check

1

Prime Factorization

Find prime factors of both numbers

2

Find Common Factors

Identify shared prime factors

3

Check Result

If only common factor is 1, they're coprime

Understanding Relatively Prime Numbers

What are Relatively Prime Numbers?

Relatively prime numbers, also called coprime numbers, are pairs of natural numbers that have only 1 as their common factor. This means no other number can divide both numbers evenly.

Key Properties

  • The GCD (Greatest Common Divisor) of coprime numbers is always 1
  • Coprime numbers don't have to be prime numbers themselves
  • If two numbers share any prime factor, they cannot be coprime
  • The number 1 is coprime with every positive integer

Algorithm: Euclidean Method

GCD(a, b) = GCD(b, a mod b)
If GCD(a, b) = 1, then a and b are coprime

Sets of Numbers

  • Setwise Coprime: GCD of all numbers in the set is 1
  • Pairwise Coprime: Every pair in the set is coprime
  • Pairwise coprime implies setwise coprime, but not vice versa

Example: The set 15 is setwise coprime (GCD = 1) but not pairwise coprime since GCD(6,10) = 2.