171 is an odd natural number between 170 and 172.
171 is a Harshad number, divisible by the sum of its digits.
171 is a palindromic number and an undulating number.
171 is a triangular number and a 13-gonal and 58-gonal number.
171 is a repdigit in base 7.
And from the FDIC:
171 is the number of banks which are currently on the FDIC list of unstable banks....
And an unreliable source says Citibank was not on that list...