This means 1 and 7 are the only factors of 7. So, 7 is a prime number because it could not be divided into groups of equal numbers. Definition of a Prime Number: Any whole number greater than 1 that is divisible only by 1 and itself, is defined as a prime number.
What are the numbers between 10 and 20?
Answer and Explanation: There are seven composite numbers between 10 and 20. These are 10, 12, 14, 15, 16, 18, and 20.
Which number between 10 and 20 is not a prime number?
The numbers 11 , 13 , 17 and 19 are all prime numbers between 10 and 20 .
Which of the following is a prime number between 1 and 10?
Prime numbers between 1 and 10 are 2, 3, 5, 7.
Are there any numbers between 1 and 20 that have 5 factors?
This means that of all the numbers from 1 to 20, the only numbers we need to look at again are the square numbers: 1, 4, 9, 16. It would seem that the largest one is most likely to have 5 factors, so let’s look at 16 first.
What kind of number is between 1 and 20?
Eduardo thinks of a number between 1 and 20 that has exactly 5 factors. What number is he thinking of? | Socratic Eduardo thinks of a number between 1 and 20 that has exactly 5 factors. What number is he thinking of? It is apparent that a number cannot be a prime number, if it has exactly 5 factors. So it is among {4,6,8,10,12,14,16,18,20}
What are the factors of the number 1?
Factors of 10: 1, 2, 5, 10. Factors of 11: 1, 11. Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 13: 1, 13. Factors of 14: 1, 2, 7, 14. Factors of 15: 1, 3, 5, 15. Factors of 16: 1, 2, 4, 8, 16. Factors of 17: 1, 17. Factors of 18: 1, 2, 3, 6, 9, 18.
How many natural numbers have exactly 4 factors?
Thus, there are 2 + 30 = 32 numbers that have exactly 4 factors (divisors). The formula for number of factors of a number given the prime factors of the number in the form p 1 e 1 ∗ p 2 e 2 ∗ p 3 e 3 ∗… ∗ p n e n (where p i is prime and e i is a natural number) is simply ∏ k = 0 n e k + 1.
