21170456173 has 4 divisors (see below), whose sum is σ = 21175157920. Its totient is φ = 21165754428.

The previous prime is 21170456161. The next prime is 21170456179. The reversal of 21170456173 is 37165407112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21170456173 - 2⁹ = 21170455661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170456179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2344113 + ... + 2353126.

It is an arithmetic number, because the mean of its divisors is an integer number (5293789480).

Almost surely, 2^21170456173 is an apocalyptic number.

It is an amenable number.

21170456173 is a deficient number, since it is larger than the sum of its proper divisors (4701747).

21170456173 is an equidigital number, since it uses as much as digits as its factorization.

21170456173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4701746.

The product of its (nonzero) digits is 35280, while the sum is 37.

The spelling of 21170456173 in words is "twenty-one billion, one hundred seventy million, four hundred fifty-six thousand, one hundred seventy-three".