Problem

Source: 2019 Saudi Arabia March Camp Test 3.3

Tags: Coloring, combinatorics



All of the numbers $1, 2,3,...,1000000$ are initially colored black. On each move it is possible to choose the number $x$ (among the colored numbers) and change the color of $x$ and of all of the numbers that are not co-prime with $x$ (black into white, white into black). Is it possible to color all of the numbers white?