129

The number 129 is a natural number that follows 128 and precedes 130 in the sequence of integers. It is classified as an odd number and is composed of three digits. In its prime factorization, 129 is expressed as the product of prime numbers 3 and 43, written as 3 × 43, indicating it is a composite number.

In mathematics, 129 has several notable properties. It is a Hodges number and an 8-gonal number, meaning it can be represented as a geometric shape with eight sides. It is also a deficient number because the sum of its proper divisors (1, 3, 43, 129) is 48, which is less than itself.

The number 129 appears in various contexts outside pure mathematics. In technology, it is used as a port number in networking protocols, specifically as a default port for certain services. In history, the year 129 AD is associated with events within the Roman Empire and other ancient civilizations, marking developments in governance and culture.

In cultural references, 129 does not have widespread symbolic significance but can be part of numerical identifiers, such as addresses, model numbers, or cataloging systems. The number also appears in scientific contexts; for example, in chemistry, it is the atomic number of the element ununnilium (now called element 129), which remains hypothetical and yet to be discovered.

Overall, 129 is a composite number with interesting mathematical properties, and it appears in various fields ranging from technology to history.