558

558 = 2 x 3² x 31.

558 is a divisor of 25³ - 1. It is also a divisor of the sum of the largest prime factors of the first 558 positive integers.

558 in base 3 and base 4 starts off with the same three digits: 202200 and 20232.

The sum of the digits of 558 is six times the number digits: 5 + 5 + 8 = 18 = 6 x 3. 558 and 558² (= 311,364) have the same digit sum.

558 is the sum of no fewer than 17 fourth powers.

558 is in the title of an episode of Star Trek: Deep Space Nine: "The Siege of AR-558".

Source: Prime Curios!