I think what the person might have meant was factoring a large composite number made up of two large prime numbers. It really is factoring large semiprimes. To

I think what the person might have meant was factoring a large composite number made up of two large prime numbers. It really is factoring large semiprimes. To make it even more confusing finding the prime factors out of any positive integer is called prime factorization. I totally get why people would say factoring large primes even though that is totally incorrect.