OG困惑: 数factor时1到底算不算??

OG11,  181,  209题:

How many different positive integers are factors of 441?

答案9, 后面解释列出: 1, 3, 7, 9, 21, 49, 63, 147 and 441, 包括1

P185, 241题:

If the integer n has exactly three positive divisors, including 1 and n, how many positive divisor does n^2 have?

答案5, 包括1

P186, 249题:

If n is a positive integer less than 200 and 14n/60 is an integer, then n has how many different positive prime factors?

答案3, 后面解释列举: 2, 3, 5, 没有包括1

这个这个.....到底数factor时什么时候包括1, 什么时候不包括啊?? 向大家请教啊~~