+- MKLab (https://mklab.gr)
+-- Forum: [INDEX] (https://mklab.gr/forumdisplay.php?fid=1)
+--- Forum: MATHEMATICS (https://mklab.gr/forumdisplay.php?fid=3)
+---- Forum: ARTICLES (https://mklab.gr/forumdisplay.php?fid=13)
+---- Thread: Euler’s Totient Theorem (/showthread.php?tid=823)
Euler’s Totient Theorem - mklabgr - 07-03-2026
Euler’s Totient Theorem
[/url]
Summary
The article explains Euler’s Totient Theorem through the idea of “coprime numbers,” meaning integers that share no common factors other than 1. It introduces Euler’s totient function φ(n), which simply counts how many numbers from 1 to n are coprime with n (for example, φ(8)=4 because 1, 3, 5, and 7 work).
From there, it shows how Euler discovered a powerful generalization of Fermat’s Little Theorem: instead of working only with primes, the same kind of modular arithmetic result holds for any number n, as long as you use φ(n) in place of p−1.
In essence, if a is coprime to n, then a raised to the power φ(n) leaves a remainder of 1 when divided by n. The article highlights how this simple-looking idea connects deep properties of numbers, extends results originally known only for primes, and underpins modern applications like cryptography, making it one of Euler’s most elegant and influential insights in number theory.
[url=https://richardelwes.co.uk/2013/04/14/eulers-totient-theorem/]ARTICLE