231021812173 has 4 divisors (see below), whose sum is σ = 231135674140. Its totient is φ = 230907950208.

The previous prime is 231021812167. The next prime is 231021812209. The reversal of 231021812173 is 371218120132.

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 123557171049 + 107464641124 = 351507^2 + 327818^2 .

It is a cyclic number.

It is not a de Polignac number, because 231021812173 - 2¹³ = 231021803981 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 (231021812113) 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, 56927940 + ... + 56931997.

It is an arithmetic number, because the mean of its divisors is an integer number (57783918535).

Almost surely, 2^231021812173 is an apocalyptic number.

It is an amenable number.

231021812173 is a deficient number, since it is larger than the sum of its proper divisors (113861967).

231021812173 is a wasteful number, since it uses less digits than its factorization.

231021812173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113861966.

The product of its (nonzero) digits is 4032, while the sum is 31.

The spelling of 231021812173 in words is "two hundred thirty-one billion, twenty-one million, eight hundred twelve thousand, one hundred seventy-three".