Problem 342
The totient of a square is a cube

Consider the number 50.
502 = 2500 = 22× 54, so φ(2500) = 2 × 4 × 53 = 8 × 53 = 23× 53. 1
So 2500 is a square and φ(2500) is a cube.

Find the sum of all numbers n, 1 &lt n < 1010 such that φ(n2) is a cube.

1 φ denotes Euler's totient function.

These problems are part of Project Euler and are licensed under CC BY-NC-SA 2.0 UK

http://projecteuler.net/problem=342