Question 1113045:  What is the greatest prime you must consider to test whether 1726 is prime?  
 Found 2 solutions by  rothauserc, Alan3354: Answer by rothauserc(4718)      (Show Source):  Answer by Alan3354(69443)      (Show Source): 
You can  put this solution on YOUR website! What is the greatest prime you must consider to test whether 1726 is prime?  
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It's obviously not prime since it's an even number. 
The greatest prime that much be considered is 2. 
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To test 863. 
You can try to factor it by dividing it by all odd numbers, but it's not necessary, since if 3 is not a factor no multiple of 3 can be a factor. 
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Test it with all prime numbers, 3, 7, 11, 13 etc. 
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sqrt(863) =~ 29 --> that's the largest number you have to try. 
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3, 5, 7, 11, 13, 17, 19, 23 & 29 
 
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