The latest articles on DEV Community by Marcel van Dinteren (@marcel_vandinteren_477b0). https://dev.to/marcel_vandinteren_477b0 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3830039%2F67336609-a092-4cb6-8e7c-7e910ab34d81.jpg https://dev.to/marcel_vandinteren_477b0 en Marcel van Dinteren Tue, 17 Mar 2026 20:38:17 +0000 https://dev.to/marcel_vandinteren_477b0/numclass-a-python-cli-that-classifies-integers-into-200-number-theory-properties-looking-for-h18 https://dev.to/marcel_vandinteren_477b0/numclass-a-python-cli-that-classifies-integers-into-200-number-theory-properties-looking-for-h18 <p>Hi everyone,</p> <p>What if you could instantly see 200+ mathematical properties of any integer?</p> <p>Prime, perfect, abundant — those are well known. But there are hundreds of lesser-known classifications, many buried in OEIS or scattered across number theory literature.</p> <p>I wanted a way to explore these properties systematically, especially for large integers where performance becomes a real constraint. That led me to build a Python CLI tool that classifies integers into 200+ number-theory properties, with a focus on speed and extensibility.</p> <p>Examples of things it can detect:</p> <p>• perfect / abundant / weird numbers<br> • Mersenne primes and primorial numbers<br> • amicable, sociable and aspiring numbers (aliquot sequences)<br> • Carmichael numbers and other pseudoprimes<br> • narcissistic, Kaprekar and happy numbers<br> • palindromic and truncatable primes<br> • taxicab numbers (Hardy–Ramanujan style cube sums)<br> • Fibonacci, Lucas, Pell and Padovan numbers<br> • triangular, pentagonal and other figurate numbers<br> • strange curiosities like Belphegor’s prime, vampire numbers and Munchausen numbers</p> <p>The current version contains 205 atomic classifiers plus 27 intersections (232 properties in total).</p> <p>Example output:</p> <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2Ffkuu9juc10u2aei5148m.jpg" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2Ffkuu9juc10u2aei5148m.jpg" alt=" " width="800" height="1082"></a></p> <p>Some features:</p> <p>• 200+ classifiers<br> • extensible plugin-like architecture<br> • configurable profiles (fast vs heavy computations)<br> • OEIS sequence integration<br> • support for very large integers (100000 digits by default)<br> • explanations for each classification</p> <p>The project is open source:</p> <p><a href="https://github.com/c788630/Numclass" rel="noopener noreferrer">https://github.com/c788630/Numclass</a></p> <p>I’m now looking for people who would like to test it, especially:</p> <p>• mathematicians<br> • Python developers<br> • people interested in number theory<br> • anyone who likes exploring interesting integer properties</p> <p>If you decide to try it out, I would really appreciate feedback on:</p> <p>• usability of the CLI<br> • additional number-theory properties to implement<br> • performance for very large numbers<br> • any issues or bugs you encounter</p> <p>There are also a few small Easter eggs hidden in the program (including Klingon number input), so feel free to explore 🙂</p> <p>Installation instructions and documentation are available in the repository (docs folder).</p> python cli opensource programming