891

891 = 3⁴ x 11.

891 is an octahedral number.

891 is the smallest number that is the reversal of the sum of its proper substrings: 8 + 9 + 1 + 89 + 91 = 198.

891 is 031323 in base 4 and 1200 in base 9.

NGC 891 is a spiral galaxy in the constellation Andromeda, discovered by William Herschel in 1784.

Source: Number Gossip