159 (number)

159 is a natural number that follows 158 and precedes 160. It is an odd number and also a composite number, meaning it has divisors other than 1 and itself.

Numbers of this type are defined by how they factor, how they appear in different number systems, and their relationships to well-known mathematical properties. 159 is written as CLIX when using Roman numerals.

Factorization and divisors

159 factors as 3 × 53. Both of these are prime numbers, making 159 a semiprime—a number that is the product of exactly two prime numbers. All its divisors are 1, 3, 53, and 159. The sum of the proper divisors (1 + 3 + 53) is 57, which is less than 159, so 159 is a deficient number.

Divisibility by 3 can be verified by adding the digits: 1 + 5 + 9 = 15, and 15 is divisible by 3. This is the standard test for divisibility by 3.

Other number bases

In binary, 159 is 10011111. In hexadecimal, it is 9F. In octal, it is 237.

Mathematical properties

159 is a Woodall number, which has the form n × 2^n − 1; when n equals 5, 5 × 2^5 − 1 = 159. It is also equal to the sum of three consecutive prime numbers: 47 + 53 + 59 = 159.