SOLUTION: What is the greatest prime that must be concidered to test whether 671 is prime?

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Question 1027857: What is the greatest prime that must be concidered to test whether 671 is prime?
Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52834) About Me  (Show Source):
You can put this solution on YOUR website!
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What is the greatest prime that must be considered to test whether 671 is prime?
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sqrt%28671%29 = 25.9 (approximately).

So the greatest prime you are asking for is 23.


Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
What is the greatest prime that must be concidered to test whether 671 is prime?
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It depends on your method.
If you test primes in order, you'll find that 11 is a factor, leaving 61 (671 = 11*61).
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Then checking 61 requires testing to INT(sqrt(61)) = 7
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