MathCastle
Number TheorySuperchallengeFactors & Multiples

Factors & Multiples · Superchallenge problem

Compute ∑d∣360lcm⁡ ⁣(d, 360d)\displaystyle\sum_{d \mid 360} \operatorname{lcm}\!\left(d,\ \dfrac{360}{d}\right), where the sum runs over all positive divisors dd of 360360.