198

198 is the natural number that follows 197 and precedes 199. In mathematics, it is an even composite number with prime factorization 2 × 3^2 × 11. It has 12 positive divisors: 1, 2, 3, 6, 9, 11, 18, 22, 33, 66, 99, and 198. The sum of its proper divisors is 270, which makes 198 an abundant number.

In base 10, 198 is a Harshad (Niven) number, since the sum of its digits is 1 + 9 + 8 = 18 and 198 is divisible by 18 (198 ÷ 18 = 11). Its standard numeral representations include binary 11000110, octal 306, and hexadecimal C6. In Roman numerals, 198 is commonly written as CXCVIII.

Numerically, 198 can be expressed as 9 × 22 and as 2 × 3^2 × 11, reflecting its factorization in different forms. It is also a member of several integer sequences through its properties as an even, composite, and abundant number.

Historically, the integers 198 CE and 198 BCE appear in the chronology of the Julian and other calendar systems, where they denote years in the respective eras. As a number, 198 is primarily of interest in number theory and arithmetic discussions, with its divisors, base representations, and factorization serving as typical examples.