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84 Find the number of integers between 1 and200, each of which has 10 divisors. |
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Answer» If there is an even number of divisors, then the product of an even number of negatives is positive. The product of an odd number of negatives is negative. The only numbers that have an odd number of divisors are perfect squares, so it suffices to find all the negative perfect squaresThe largest one is then(14)^2=196, which has factors1,2,4,7,14,28,49,98,196Therefore, there are1414integers. unable to understand |
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