1231791439321 has 3 divisors (see below), whose sum is σ = 1231792549183. Its totient is φ = 1231790329460.

The previous prime is 1231791439313. The next prime is 1231791439367. The reversal of 1231791439321 is 1239341971321.

The square root of 1231791439321 is 1109861.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 5766731721 + 1226024707600 = 75939^2 + 1107260^2 .

It is not a de Polignac number, because 1231791439321 - 2³ = 1231791439313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231791439421) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 554931 + ... + 1664791.

Almost surely, 2^{1231791439321} is an apocalyptic number.

1231791439321 is the 1109861-st square number.

1231791439321 is the 554931-st centered octagonal number.

It is an amenable number.

1231791439321 is a deficient number, since it is larger than the sum of its proper divisors (1109862).

1231791439321 is an frugal number, since it uses more digits than its factorization.

1231791439321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2219722 (or 1109861 counting only the distinct ones).

The product of its digits is 244944, while the sum is 46.

It can be divided in two parts, 123179 and 1439321, that added together give a square (1562500 = 1250²).

The spelling of 1231791439321 in words is "one trillion, two hundred thirty-one billion, seven hundred ninety-one million, four hundred thirty-nine thousand, three hundred twenty-one".