Question 1173053
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Decomposition of the integer number of 40 into the profuct of prime integers is


    40 = {{{2^3*5}}}.


From this decomposition, it is clear that the number which multiplied by 40 gives a perfect square is 2*5 = 10.


Indeed,  10*40 = 400 = {{{20^2}}}.


Also, it is clear from the decomposition, that 2*5 = 10 is the MINIMAL integer number with such a property.
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