188 (number)

188 is a natural number that follows 187 and precedes 189. It is an even number, meaning it is divisible by 2 with no remainder. It is also a composite number, as it has divisors other than 1 and itself.

Numbers of this kind are used in elementary mathematics, counting, and notation systems of various types, such as historical years or road numbers. The value of the number does not change when the numbering system is changed, but the written representation does.

Mathematical properties

188 can be factored into prime numbers as follows: 188 = 2 × 2 × 47, or 2² × 47. Its divisors are 1, 2, 4, 47, 94, and 188. The sum of all divisors is 336; excluding 188 itself, the sum is 148, which is less than 188. Therefore 188 is a deficient number.

The sum of its digits (1 + 8 + 8) is 17. 188 is not a perfect square, since 13² = 169 and 14² = 196 are both different from it. It is stated to be a palindrome readable the same way from both ends (when 188 is reversed it becomes 881, so it is not a palindrome—see note below).

Other numbering systems

In Roman numerals, 188 is written CLXXXVIII. In binary it is 10111100, and in hexadecimal it is BC. In octal it is 274.

Other uses

The number 188 is used for years in the Gregorian calendar (the year 188 CE and 188 BCE), and also for road designations, telephone area codes, and identification numbers in various countries. These uses are determined by local agreement and are not mathematical properties.