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Both calculators run independently — change the inputs on either side to compare results.

Divisibility Rules Checker

Instantly check whether a number is divisible by 2–13 or a custom divisor, with plain-English explanations of each rule. Ideal for students learning number theory or anyone verifying factors quickly.

Number to Check

Check Divisibility By

Custom Divisor (if custom selected)

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Number Theory

Collatz Conjecture Analyzer

Trace the Collatz sequence from any starting integer — halving evens and applying 3n+1 to odds — until reaching 1. Reveals stopping time, maximum value reached, and sequence statistics for the famous unsolved 3n+1 problem.

Starting Number

Maximum Iterations

Fill in the required fields to see your result.

Key differences

	Divisibility Rules Checker	Collatz Conjecture Analyzer
Category	Number Theory	Number Theory
Inputs required	3	2
Result	Divisibility Results	Collatz Analysis
What it does	Instantly check whether a number is divisible by 2–13 or a custom divisor, with plain-English explanations of each rule. Ideal for students learning number theory or anyone verifying factors quickly.	Trace the Collatz sequence from any starting integer — halving evens and applying 3n+1 to odds — until reaching 1. Reveals stopping time, maximum value reached, and sequence statistics for the famous unsolved 3n+1 problem.