Born in 1707, Leonhard Euler was the son of a Protestant minister from the vicinity of Basel, Switzerland. With the aim of pursuing a career in theology, Euler entered the University of Basel at the age of thirteen, where he was tutored in mathematics by Johann Bernoulli (of the famous Bernoulli family of mathematicians). He developed an interest in mathematics and eventually authored more than 700 books and papers. This paper discusses Euler's work on the solution to Diophantine equations (marking the early history of algebraic number theory), analytic number theory, arithmetic functions, and his theory of partitions.