MIRACL (Multiprecision Integer and Rational Arithmetic C/C++ Library) is a famous library used most of the time for implementing number-theoretic based methods of cryptography. I don't know how to code in C and C++ so I was wondering are there other libraries like MIRACL but for python?
For Python, you can use Charm: https://jhuisi.github.io/charm/install_source.html
In Charm, you will find a wide range of implemented schemes that can be easily used, please see this example for the RSA public key encryption https://jhuisi.github.io/charm/charm/schemes/pkenc/pkenc_rsa.html
This is a list of all the implemented cryptographic protocols: https://jhuisi.github.io/charm/schemes.html