Coprime integers, also known as relatively prime integers, are two or more numbers that have no common positive integer factors other than 1. This means their greatest common divisor (GCD) is 1, making them fundamental in number theory and useful in various applications like cryptography and modular arithmetic.
Euler's Product Formula establishes a profound connection between prime numbers and the Riemann zeta function, revealing that the zeta function can be expressed as an infinite product over all prime numbers. This formula underscores the fundamental role of primes in number theory and highlights the deep interplay between multiplicative structures and analytic properties of functions.