164

164 is a natural number that follows 163 and precedes 165. In everyday counting and in mathematics, it is an even composite number.

Its prime factorization is 2^2 × 41, so its divisors are 1, 2, 4, 41, 82, and 164. The sum of its positive divisors is 294. As a result, 164 is not prime, not a prime power (other than the 2^2 factor), and it is not a square or a Fibonacci number. In modular arithmetic, 164 ≡ 2 (mod 3) and 164 ≡ 0 (mod 4).

In base representations, 164 is written as 10100100 in binary, 244 in octal, and A4 in hexadecimal.

164 Eva is a large main-belt asteroid discovered by Johann Palisa in 1876. It is designated as the 164th asteroid to be discovered.

Historically, the year AD 164 was a period within the reign of Emperor Marcus Aurelius, with some sources noting the onset of the Antonine Plague in the surrounding years, around 164–165 CE.