Two questions: one question: a number is not only a multiple of 21, but also a divisor of 21. What is the number? What is the prime factor when it is decomposed? The second question: a natural number divided by 2, 3, 4, 5, the result is more than 1, how many such numbers? What is the smallest?

Two questions: one question: a number is not only a multiple of 21, but also a divisor of 21. What is the number? What is the prime factor when it is decomposed? The second question: a natural number divided by 2, 3, 4, 5, the result is more than 1, how many such numbers? What is the smallest?

One question: a number is not only a multiple of 21, but also a divisor of 21. What is the number?
This number can only be 21. A number itself is both its divisor and its multiple
21 = 3×7
Two questions: a natural number divided by 2, 3, 4, 5, the result is more than 1, how many such numbers? What is the smallest?
Such numbers are the common multiples of 2, 3, 4 and 5. There are countless numbers
2. The least common multiple of 3, 4 and 5 is 60, so the minimum number is 61
The rest of these numbers are n 60 + 1, such as 121, 181