173 is:

• an odd number.
• a deficient number.
• an odious number.
• a balanced prime.
• an Eisenstein prime with no imaginary part.
• a Sophie Germain prime.
• an inconsummate number.
• the sum of 2 squares: 2^2 + 13^2.
• the sum of three consecutive prime numbers: 53 + 59 + 61.
• palindromic in bases 3 (20102), 9 (212) and 172 (11).