Fancy factors

Number Theory Level 3

Which of the following is true about 1234567?

It is not divisible by an integer from 2 to 100 inclusive. It is a perfect cube. It is a prime number. Two of the other options are correct.

1 solution

Chrishan Silva
Aug 28, 2014

The factors of 1234567: excluding 1 and the number itself are 127 and 9721. Yes, both of these are primes.

Can option "Two of these options are correct" be correct? I think it is because option "It is not divisible by an integer from 2 to 100 inclusive" is correct but according to wording of option(Two of these options are correct) if we select option (Two of these options are correct) then automatically this option should be true.

shivamani patil - 6 years, 7 months ago

Yes you are right.Tell that to @Calvin Lin

Rajdeep Dhingra - 6 years, 4 months ago

That had been what I answered for the same reason.

Sharky Kesa - 6 years, 4 months ago

$1234567$ is neither a prime nor a perfect cube. I think the suitable term to be used for it is "pseudoprime".

Prasun Biswas - 6 years, 4 months ago

Given the poor phrasing of the problem, I agree that "two of these options are correct" has an interpretation that would make it correct. Those who previously selected this answer have been marked correct. The correct answer remains as "It is not divisible by an integer from 2 to 100 inclusive".

In future, if you spot any errors with a problem, you can “report” it by selecting the “dot dot dot” menu in the lower right corner. You will get a more timely response that way.

Calvin Lin Staff - 6 years, 3 months ago

Fancy factors

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