Fill in the brackets with the appropriate prime number 45 = () + ()

Fill in the brackets with the appropriate prime number 45 = () + ()

45 = (2) + (43) 2 is the smallest prime number

The sum of the two prime numbers is 81, so what is the product of the two prime numbers?

Prime numbers are all odd [except 2], and their sum should be even. Now if the sum of these two prime numbers is 81, then one of them must be 2, so the other is 79, then their product is 158

The sum of the reciprocal of the three prime numbers is 71105. The three prime numbers are______ 、______ 、______ ．

According to the meaning and analysis of the question, 105 is decomposed into three prime factors: 105 = 3 × 5 × 7; 13 + 15 + 17 = 35105 + 21105 + 15105 = 71105. Therefore, the three prime numbers are 3, 5 and 7 respectively. So the answer is: 3, 5 and 7