173021 has 2 divisors, whose sum is σ = 173022. Its totient is φ = 173020.

The previous prime is 172999. The next prime is 173023. The reversal of 173021 is 120371.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148996 + 24025 = 386^2 + 155^2 .

It is an emirp because it is prime and its reverse (120371) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-173021 is a prime.

It is a Sophie Germain prime.

Together with 173023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 172987 and 173005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (173023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86510 + 86511.

It is an arithmetic number, because the mean of its divisors is an integer number (86511).

2¹⁷³⁰²¹ is an apocalyptic number.

It is an amenable number.

173021 is a deficient number, since it is larger than the sum of its proper divisors (1).

173021 is an equidigital number, since it uses as much as digits as its factorization.

173021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42, while the sum is 14.

The square root of 173021 is about 415.9579305651. The cubic root of 173021 is about 55.7228010528.

Adding to 173021 its reverse (120371), we get a palindrome (293392).

Subtracting from 173021 its reverse (120371), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 173021 in words is "one hundred seventy-three thousand, twenty-one", and thus it is an iban number.