The purpose of this paper is to investigate an ℓ-ring structure of algebraic integers
from an arithmetic point of view. We endow the algebra D of hyperbolic numbers
with its standard f-algebra structure [7]. We introduce the ring of hyperbolic
integers Zh as a sub f-ring of the ring ZD
of integers of D. Next, we prove
that Zh is the unique, up to ring isomorphism, Archimedean f-ring of quadratic
integers. Our study focuses on arithmetic properties of Zh related to its latticeordered
structure. We show that many basic properties of the ring of integers Z
such as primes, unique factorization theorem and the notions of floor and ceiling
functions can be extended to Zh. A surprising fact is that prime numbers seen as
hyperbolic integers are semiprimes. We also obtain some properties of hyperbolic
Gaussian integers. As an application, we discuss the Dirichlet divisor problem
using hyperbolic intervals.