MathDB
Zeros taker

Source: ITAMO 2021 - Problem 1

May 8, 2021
number theory

Problem Statement

A positive integer mm is said to be \emph{zero taker} if there exists a positive integer kk such that:
kk is a perfect square; mm divides kk; the decimal expression of kk contains at least 20212021 '0' digits, but the last digit of kk is not equal to 00.
Find all positive integers that are zero takers.