Radical of an integer

In number theory, the radical of an integer is the product of its unique prime factors. The radical of an integer ${\displaystyle n}$ is written ${\displaystyle \mathrm {rad} \,n}$. The radical is an important part of the abc conjecture, one of the most important unsolved problems in mathematics.^[1]

1. ↑ Gowers, Timothy (2008). "V.1 The ABC Conjecture". The Princeton Companion to Mathematics. Princeton University Press. p. 681.