Tell me what is the cipher

Question

Encryption

I came across a problem like this: “There is a large number. It is known that it is the product of two primes. Find its multipliers.
Yesterday, over a bottle of a conversation with a friend, I remembered, told, he said that it was connected with some kind of cipher (the public key is a number, the multipliers are the keys that the client and server know, like so). The conversation went on, but I forgot to clarify.
The question is - is there such a method and, if so, what is it called?

Answer 1

Apparently, it was about RSA

Answer 2

I came across a problem like this: “There is a large number. It is known that it is the product of two primes. Find its multipliers.

Where are these tasks given? If you find a solution that works out in an acceptable time, you will get, as far as I remember, a million dollars and, along the way, arrange a natural disaster for a significant part of modern cryptography.