231311313221 has 4 divisors (see below), whose sum is σ = 233132662272. Its totient is φ = 229489964172.

The previous prime is 231311313199. The next prime is 231311313223. The reversal of 231311313221 is 122313113132.

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 231311313221 - 2⁶ = 231311313157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231311313223) 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, 910674335 + ... + 910674588.

It is an arithmetic number, because the mean of its divisors is an integer number (58283165568).

Almost surely, 2^231311313221 is an apocalyptic number.

It is an amenable number.

231311313221 is a deficient number, since it is larger than the sum of its proper divisors (1821349051).

231311313221 is a wasteful number, since it uses less digits than its factorization.

231311313221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1821349050.

The product of its digits is 648, while the sum is 23.

Adding to 231311313221 its reverse (122313113132), we get a palindrome (353624426353).

The spelling of 231311313221 in words is "two hundred thirty-one billion, three hundred eleven million, three hundred thirteen thousand, two hundred twenty-one".