望详细解答，谢谢 What is the least positive integer that is not a factor of 25! and is not a prime

望详细解答，谢谢 What is the least positive integer that is not a factor of 25! and is not a prime

positive integers from smallest:
1,2,3,4,...

1 is a factor, 25!=1*25!
2 is a prime number
3 is a prime number
4 is a factor,25!=4*1*2*3*5*6*...*25

25!指的是25阶乘=25*24*...*1
5显然是factor
6,7,8,9,10,...,25显然都是factor
26=2*13也是
27=3*3*3，25!中有3和9，所以也是factor
28=4*7,factor
29是prime
30=3*10
31prime
32=4*8,factor
33=3*11,factor
34=2*17,factor
35=5*7,factor
36=4*9,factor
37prime
38=2*19,factor
39prime
40=4*10,factor
41prime
42=2*21factor
43prime
44=4*11factor
45=5*9factor
46=2*23factor
47prime
48=6*8factor
49=7*7,25!包含7和14，factor
50=5*10factor
51=3*17factor
52=4*13factor
53prime
54=2*3*9,factor
55=5*11,factor
56=7*8,factor
57=3*19,factor
58=2*29,not a factor and not a prime

So 58 is the least positive integer that is not a factor of 25! and is not a prime number.

4. Positive intergers are whole numbers larger than zero, 1, 2,3, etc. Prime numbers are numbers that only have two factors, 1 and itself. Factors of 25 are numbers that can be divided into 25, i.e. 1, 5, 25. Now, 1 is a factor of 25, 2 and 3 are prime numbers, so 4 is the smallest positive integer that isn't a factor of 25.

什么是最小的positive integer, 不是25 的factor, 又不能是prime number Positive integer: 1, 2, 3, 4, 5, 6。。。 Factor of 25: 1, 5, 25 (剩下 2， 3， 4， 6。。。) Prime number 2, 3, 5, 7, 11, 13… (排除2 和 3 ） 答案应该是 4 ， 最小的 positive integer， 不是25 的factor, 又不能是prime number ** 猫迷英语专家团提供【Real。American。English。】