This research and educational poster presents a key part of the Shor's factorization, namely the quantum implementation of the modular exponentiation function. In contrast to other works on a similar topic, where Shor's factorizations of small numbers such as 15, 21 or 35 are presented, an implementation of a modular exponentiation function applicable to the Shor's factorization of the number 247 is presented here. This poster shows one of the simpler ways of constructing a quantum circuit of a modular exponentiation function that allows this factorization. At the bottom of the poster, the measured results are presented and the sought factors are calculated, thus confirming the correct implementation.