og-ds243

243 if the integer n is greater than 1, is n equal to 2?

1. n has exactly two positive factors.
2. the difference of any two distinct positive factors of n is odd.

the answer is B.

but n=6---->n=2x3 or n=14---->n=2x7. 3-2=1,7-2=5
n is not sure 2. am i wrong?

For any integer N, it has at least 1 and N as its factor.

So N-1 must be odd, making N even. Thus N has factor 2. If N is not 2, then N-2 is even, contradicting with B). so N is 2.

有个疑问，要是N is 2, then N-2=0也是偶数啊？

这题还是很糊涂的说，请nn帮帮忙。