840

840 = 2 x 2 x 2 x 3 x 5 x 7.

840 is the least common multiple of the first 8 positive integers (it is the smallest number divisible by 1 through 8).

840 is the smallest number with exactly 32 divisors (A005179 and A037992).

840 is is 11330 in base 5 and 1133 in base 9.

840 is the sum of a twin prime pair (A054735): 840 = 419 + 421.

840 is the sum of distinct factorials (A059590): 840 = 6! + 5!

840 is the smallest positive even integer that is an unordered sum of two primes in exactly 51 ways (A023036).

Source: What's Special About This Number?