270

270 = 2 x 3³ x 5.

270 is a number n such that n² + 1 is prime: 270² + 1 = 72901, a prime.

270 is the smallest number whose sum of divisors (720) equals 10 times its reverse.

10! has 270 divisors.

270 is a number n such that 6n - 1 and 6n + 1 are twin primes: 6*270 - 1 = 1619 and 6*270 + 1 = 1621.

270 is one the standard numerical values for resistors.

Source: Number Gossip