Uploaded January 2021 | Updated September 2026, 1 week ago

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This lecture is part of an online undergraduate course on the theory of numbers.

Multiplicative functions are functions such that f(mn)=f(m)f(n) whenever m and n are coprime. We discuss some examples, such as the number of divisors, the sum of the divisors, and Euler's totient function.




For the other lectures in the course see youtube.com/playlist?list=PL8yHsr3EFj52Qf7lc3HHvHRdIysxEcj1H