【Question 3】A natural number greater than 1 that can only be divided by 1 and itself, like $2,3,5,7$, is called a prime number. Decompose 2015 into the sum of 100 prime numbers, requiring that the largest prime number be as small as possible. What is this largest prime number? $\qquad$ -
Analysis: The requirement is for the largest prime number to be as small as possible, which means the 100 numbers should be as close to each other as possible.
$$
2015 \div 100=20 \ldots 15
$$

Therefore, the largest prime number must be greater than 20, and the smallest prime number greater than 20 is 23. $2015=23 \times 86+11 \times 1+2 \times 13$ (2015 can be expressed as the sum of 86 instances of 23, 1 instance of 11, and 13 instances of 2). Therefore, this largest prime number is 23.