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2025 using primes

Table of Contents

Puzzle

The number 2025 is not prime. As a matter of fact, it’s a perfect square: 2025=4522025 = 452. You cannot make 20252025 by adding two distinct primes. To do so, you’d have to add an even prime and an odd prime. The only even prime is 22, but 2025βˆ’2=20232025 βˆ’ 2 = 2023, which is not prime (it’s equal to 7βˆ™1727βˆ™172). But you can make 2025 by adding three distinct primes. For example, 661+673+691=2025661 + 673 + 691 = 2025. You can also make 2025 by adding four distinct primes: 2+659+673+691=20252 + 659 + 673 + 691 = 2025. What is the greatest number of distinct primes that add up to 2025?

Solution