Tool to test / find / check co-prime numbers (relatively prime). Two (or more) Integers are called coprimes if their GCD (greatest common divisor) is equal to 1.

dCode is free and its tools are a valuable help in games, maths, geocaching, puzzles and problems to solve every day! A suggestion ? a feedback ? a bug ? an idea ? Write to dCode!

What are coprimes/relatively primes numbers? (Definition)

Relatively prime numbers (coprimes) are numbers that share no common divisor (except 1).

Example: The number 4 has 1, 2 and 4 as divisors The number 9 has 1, 3 and 9 as divisors Numbers 4 and 9 share the number 1 as the only common divisor and so are coprimes.

How to calculate if numbers are coprimes?

Formally, in mathematics, two numbers are coprimes if the GCD (greatest common divisor) of these numbers is equal to 1. This definition can be extended to N numbers.

Example: GCD(4,6) = 2, then 4 and 6 are not coprimes.

Example:GCD (4,5,6) = 1 then 4, 5 and 6 are coprimes, but not pairwise comprime as 4 and 6 are not relatively primes.

Example:GCD (7,12) = 1 then 7 and 12 are coprimes.

How to find a coprime number with another?

dCode's calculator/checker tests numbers depending on the prime factor decomposition of the first number (and therefore its divisors) to find coprime numbers. Then check that GCD equals 1 to confirm the number.

According to the definition, yes, 1 and 1 are coprimes as GCD(1,1)=1. Moreover 1 and any positive integer are relatively primes.

Source code

dCode retains ownership of the online "Coprimes" source code. Except explicit open source licence (indicated CC / Creative Commons / free), the "Coprimes" algorithm, the applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or the "Coprimes" functions (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) and all data download, script, copy-paste, or API access for "Coprimes" are not public, same for offline use on PC, tablet, iPhone or Android ! Remainder : dCode is free to use.

Need Help ?

Please, check our dCode Discord community for help requests! NB: for encrypted messages, test our automatic cipher identifier!

Questions / Comments

Thanks to your feedback and relevant comments, dCode has developed the best 'Coprimes' tool, so feel free to write! Thank you!

Thanks to your feedback and relevant comments, dCode has developed the best 'Coprimes' tool, so feel free to write! Thank you!