174

174 = 2 x 3 x 29.

174 is a divisor of 59² - 1.

174 is the number of twin primes among the first thousand primes.

174 = 7² + 5³.

174 is the smallest number that can be written as the sum of four positive distinct squares in six ways.

In 1978, Landon Noll and Laura Nickel used a CDC Cyber 174 to prove that the Mersenne number M₂₁₇₀₁ is a prime number.

Source: Prime Curios!