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Eight Factors Only

Age 14 to 16 Short
Challenge Level

A certain positive integer has exactly eight factors.
Two of these factors are 15 and 21.

What is the sum of all eight factors?





This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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