[求助]数学请教

how many different prime numbers are factors of the positive integer n

1.four different prime numbers are factors of 2n

2.four different prime numbers are factors of n*n

条件一： 2n有四个异质因子,当2n=2*3*5*7,则n=3*5*7有3个异质因子；当2n=2^2*3*5*7,则n=2*3*5*7有四个，A错

条件二：n方有四个异质因子，因n为整数，设n^2=(a*b*c*d)^2,abcd为四个异质因子，则n=a*b*c*d，也有四个异质因子，B对。