558

558 is a natural number that follows 557 and precedes 559. It is an even, composite number with a prime factorization of 2 × 3^2 × 31. Its positive divisors are 1, 2, 3, 6, 9, 18, 31, 62, 93, 186, 279, and 558, giving it 12 divisors in total. The sum of its digits is 18, which makes 558 divisible by 3 and by 9.

In different numeral systems, 558 is written as DLVIII in Roman numerals, as 1000101110 in binary, as 1056 in octal, and as 0x22E in hexadecimal.

As a year, 558 CE refers to a point in the late ancient period, while 558 BCE belongs to the 6th century BCE. Both usages appear in historical chronology and are treated as calendar references rather than as mathematical properties.

Beyond these basic facts, 558 serves as an example of a small composite number in mathematical contexts such as teaching divisor structure, modular arithmetic, and number theory problems. Its factorization into 2 × 3^2 × 31 highlights how composite numbers can be analyzed in terms of their prime components, and its various representations across numeral systems illustrate how the same quantity is expressed differently in different notations.