21313231232231 has 4 divisors (see below), whose sum is σ = 21313296526392. Its totient is φ = 21313165938072.

The previous prime is 21313231232219. The next prime is 21313231232273. The reversal of 21313231232231 is 13223213231312.

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

It is a cyclic number.

It is not a de Polignac number, because 21313231232231 - 2¹⁰ = 21313231231207 is a prime.

It is a super-2 number, since 2×21313231232231² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21313231232194 and 21313231232203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313231532231) 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, 32154980 + ... + 32811113.

It is an arithmetic number, because the mean of its divisors is an integer number (5328324131598).

Almost surely, 2^{21313231232231} is an apocalyptic number.

21313231232231 is a deficient number, since it is larger than the sum of its proper divisors (65294161).

21313231232231 is an equidigital number, since it uses as much as digits as its factorization.

21313231232231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65294160.

The product of its digits is 7776, while the sum is 29.

Adding to 21313231232231 its reverse (13223213231312), we get a palindrome (34536444463543).

The spelling of 21313231232231 in words is "twenty-one trillion, three hundred thirteen billion, two hundred thirty-one million, two hundred thirty-two thousand, two hundred thirty-one".