21213122231 has 4 divisors (see below), whose sum is σ = 24243568272. Its totient is φ = 18182676192.

The previous prime is 21213122221. The next prime is 21213122237. The reversal of 21213122231 is 13222131212.

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 21213122231 - 2⁶ = 21213122167 is a prime.

It is a super-2 number, since 2×21213122231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213122237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1515223010 + ... + 1515223023.

It is an arithmetic number, because the mean of its divisors is an integer number (6060892068).

Almost surely, 2^21213122231 is an apocalyptic number.

21213122231 is a deficient number, since it is larger than the sum of its proper divisors (3030446041).

21213122231 is an equidigital number, since it uses as much as digits as its factorization.

21213122231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030446040.

The product of its digits is 288, while the sum is 20.

Adding to 21213122231 its reverse (13222131212), we get a palindrome (34435253443).

The spelling of 21213122231 in words is "twenty-one billion, two hundred thirteen million, one hundred twenty-two thousand, two hundred thirty-one".