73172317021 has 4 divisors (see below), whose sum is σ = 73217017692. Its totient is φ = 73127616352.

The previous prime is 73172316989. The next prime is 73172317051. The reversal of 73172317021 is 12071327137.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14953865796 + 58218451225 = 122286^2 + 241285^2 .

It is a cyclic number.

It is not a de Polignac number, because 73172317021 - 2⁵ = 73172316989 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 (73172317051) 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, 22347880 + ... + 22351153.

It is an arithmetic number, because the mean of its divisors is an integer number (18304254423).

Almost surely, 2^73172317021 is an apocalyptic number.

It is an amenable number.

73172317021 is a deficient number, since it is larger than the sum of its proper divisors (44700671).

73172317021 is a wasteful number, since it uses less digits than its factorization.

73172317021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44700670.

The product of its (nonzero) digits is 12348, while the sum is 34.

The spelling of 73172317021 in words is "seventy-three billion, one hundred seventy-two million, three hundred seventeen thousand, twenty-one".