Sum of divisors
Given an integer n, return the sum of all its positive divisors.
Perfect Number Check
Write a function that returns True if a number is perfect, i.e., equal to the sum of its proper divisors.
Abundant Number Check
Implement a function to check whether a given integer is abundant: sum of proper divisors exceeds the number.
Amicable Numbers Check
Write a function that checks if two numbers are an amicable pair by comparing sums of proper divisors.
Deficient Number Check
Write is_deficient(n) that returns True if the sum of proper divisors is less than n.
Isolate Rightmost Set Bit
Given an integer, return a number with only its rightmost set bit set.
Format date output
Parse ISO date strings and format them into a friendly US-style date output.
Week Number ISO
Given a date, return its ISO 8601 week number (1–53) without using datetime.isocalendar().
Constant Time Compare
Write a function that compares two strings without leaking length or content via timing.
Showing 25–33 of 33 challenges
Guide: free Python coding challenges
Practice Python by solving problems
PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.
How to use the arena
- Pick a category — basics, algorithms, strings, and more
- Open a challenge, read the statement, and edit the starter code
- Run tests, fix failures, then try a related quiz or tutorial lesson
Challenges vs tutorials and quizzes
Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.