PUMaC 2010 · 数论（A 组） · 第 2 题
PUMaC 2010 — Number Theory (Division A) — Problem 2
题目详情
- Find the largest positive integer n such that σ ( n ) = 28, where σ ( n ) is the sum of the divisors of n , including n . 2
解析
- Find the largest positive integer n such that σ ( n ) = 28, where σ ( n ) is the sum of the divisors of n , including n . Solution: The answer is 12. It isn’t hard to see that that is, in fact, the only value where that equation holds. 2