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MathNet 2023-part-01 — 191 problems (EN–VI) Question 27

Math Olympiad Vault · MathNet 2023-part-01 — 191 problems (EN–VI)

Question 27

Find all integers $n$ satisfying $n \geq 2$ and $\frac{\sigma(n)}{p(n)-1}=n$, in which $\sigma(n)$ denotes the sum of all positive divisors of $n$, and $p(n)$ denotes the largest prime divisor of $n$.