MathDB
What function is this, part 2???

Source: LMAO 2024 P5

June 1, 2024
number theoryfunctional equationlmao

Problem Statement

Prove that there exists a function f:NNf : \mathbb{N} \mapsto \mathbb{N} that satisfies the following:
[color=#FFFFFF]___1. For all positive integers m,nm, n we have gcd(f(m)f(n),f(mn))=f(gcd(m,n))\gcd(|f(m)-f(n)|, f(mn)) = f(\gcd(m, n)) [color=#FFFFFF]___2. For all positive integers mm, we have f(f(m))=f(m)f(f(m)) = f(m). [color=#FFFFFF]___3. For all positive integers kk, there exists a positive integer nn with 2024kf(n)2024^{k} \mid f(n).
Proposed by MV Adhitya, Archit Manas