171

171 = 3² x 19.

171 is a Harshad number, divisible by the sum of its digits (1 + 7 + 1 = 9).

171 is the 18th triangular number, the sum of the integers from 1 to 18.

If you write n consecutive digits starting with 1 and following 9 by 0, the smallest n that will give you a prime number is 171.

171 is 333 in base 7.


171 Ophelia is a large, dark asteroid discovered in 1877.

Source: Number Gossip