2016 | OriginalPaper | Chapter

# 3. Number Theory

Published in:
Guide to Discrete Mathematics

## Abstract

Number theory is the branch of mathematics that is concerned with the mathematical properties of the natural numbers and integers. These include properties such as the parity of a number; divisibility; additive and multiplicative properties; whether a number is prime or composite; the prime factors of a number; the greatest common divisor and least common multiple of two numbers; and so on. Number theory has many applications in computing: for example, the security of the RSA public key cryptographic system relies on the infeasibility of the integer factorization problem for large numbers. There are several unsolved problems in number theory: e.g., Goldbach’s Conjecture states that every even integer greater than two is the sum of two primes.