• 173² = 29929 is the smallest square that contains exactly three digits '9'.

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173 has 2 divisors, whose sum is σ = 174. Its totient is φ = 172.

The previous prime is 167. The next prime is 179. The reversal of 173 is 371.

173 is nontrivially palindromic in base 3 and base 9.

173 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It is a balanced prime because it is at equal distance from previous prime (167) and next prime (179).

It can be written as a sum of positive squares in only one way, i.e., 169 + 4 = 13^2 + 2^2 .

173 is a truncatable prime.

It is a cyclic number.

It is not a de Polignac number, because 173 - 2⁴ = 157 is a prime.

It is a Sophie Germain prime.

173 is an undulating number in base 9.

It is a Curzon number.

It is a plaindrome in base 6, base 7, base 8, base 11, base 12 and base 16.

It is a nialpdrome in base 14 and base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 173.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86 + 87.

It is an arithmetic number, because the mean of its divisors is an integer number (87).

It is an amenable number.

173 is a deficient number, since it is larger than the sum of its proper divisors (1).

173 is an equidigital number, since it uses as much as digits as its factorization.

173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21, while the sum is 11.

The square root of 173 is about 13.1529464380. The cubic root of 173 is about 5.5720546555.

The spelling of 173 in words is "one hundred seventy-three", and thus it is an aban number and an iban number.