Math CentralQuandaries & Queries


Question from Manchali:

Find a number that has 4 factors and all of them are odd numbers.

Hi Manchali,

You could choose 4 odd integers and multiply them together, say $3 \times 5 \times 7 \times 11$ which give an integer with 4 odd factors but it has many more factors than 3, 5, 7 and 11, for example 15 and 21. I expect you want an integer with exactly four factors, all of which are odd.

I would start by listing the first few odd positive integers. Multiply a few of them together as I did above. Can you find a product with exactly 4 factors?


About Math Central
* Registered trade mark of Imperial Oil Limited. Used under license.


Math Central is supported by the University of Regina and the Imperial Oil Foundation.
Quandaries & Queries page Home page University of Regina Imperial Oil Foundation