Powerful Numbers Day - September 27

Happy Powerful Numbers Day!

Powerful numbers (aka squareful numbers) are ones such that for every number dividing it that is prime or 1, the square of the divisor is also a divisor.


Powerful numbers are basically a subset of the composite numbers in addition to the number 1, and contain the square numbers as a subset.

Here's some of the arithmetic that determines powerful numbers.



We celebrate Powerful Numbers Day today because 9 and 27 are the largest powerful numbers that form a valid date: 9/27 or September 27.

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