231312715021 has 4 divisors (see below), whose sum is σ = 232865149500. Its totient is φ = 229760280544.

The previous prime is 231312714977. The next prime is 231312715033. The reversal of 231312715021 is 120517213132.

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 28915302025 + 202397412996 = 170045^2 + 449886^2 .

It is a cyclic number.

It is not a de Polignac number, because 231312715021 - 2⁹ = 231312714509 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 (231312715121) 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, 776217016 + ... + 776217313.

It is an arithmetic number, because the mean of its divisors is an integer number (58216287375).

Almost surely, 2^231312715021 is an apocalyptic number.

It is an amenable number.

231312715021 is a deficient number, since it is larger than the sum of its proper divisors (1552434479).

231312715021 is a wasteful number, since it uses less digits than its factorization.

231312715021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1552434478.

The product of its (nonzero) digits is 2520, while the sum is 28.

Adding to 231312715021 its reverse (120517213132), we get a palindrome (351829928153).

The spelling of 231312715021 in words is "two hundred thirty-one billion, three hundred twelve million, seven hundred fifteen thousand, twenty-one".