The sum over divisors of the Euler function equals $$\sum_{d\mid n}\phi(d)=n.$$

| | | | | created: 2016-09-08 09:18:32 | modified: 2019-04-07 06:13:48 | by: *guest* | references: [1272]

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[1272] **Landau, Edmund**: “Vorlesungen über Zahlentheorie, Aus der Elementaren Zahlentheorie”, S. Hirzel, Leipzig, 1927