Prime Factorization by Division Therefore, the prime factors of 60 are 2, 3, and 5.

The prime numbers between 11 and 60 are 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53 and 59.

There are – three sets of primes that sum to 100: 2 19 17, 2 31 67, and 2 37 61.

Or a number having 1, 3, 5, 7 and 9 at its units place is called an odd number. Number s which have only two factors namely 1 and the number itself are called prime numbers. For example: 2, 3, 5, 7, 11, 19, 37 etc are prime numbers.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97. All these prime numbers are odd, except for number 2. If we remove the number 2, those that remain are the answer to the question. Can you add 3 odd numbers to get 30?

We can take this as the answer because 5 and 19 both are odd prime numbers. Hence 24 is the sum of 5 and 19. Note: Knowing the definition of prime numbers and odd prime numbers is the key here. Trial and hit method is best suited for this type of question.

So, as we know that 3,7,43 are three odd prime numbers. So, if we consider these three primes, their sum is equal to 3+7+43=53.

The primitive root of a prime number n is an integer r between[1, n-1] such that the values of r^x(mod n) where x is in the range[0, n-2] are different. Return -1 if n is a non-prime number. A simple solution is to try all numbers from 2 to n-1.

Since φ(20) = φ(4)φ(5) = 2·4 = 8, it follows immediately that 20 has no primitive root.

Every prime number has a primitive root. Let p be a prime and let m be a positive integer such that p−1=mk for some integer k. As a result, we see that there are p−1 incongruent integers of order p−1 modulo p. Thus p has ϕ(p−1) primitive roots.