21321123231 has 32 divisors (see below), whose sum is σ = 28883973888. Its totient is φ = 13988712960.

The previous prime is 21321123217. The next prime is 21321123253. The reversal of 21321123231 is 13232112312.

It is a de Polignac number, because none of the positive numbers 2^k-21321123231 is a prime.

It is a super-2 number, since 2×21321123231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21321123198 and 21321123207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321123431) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26751325 + ... + 26752121.

It is an arithmetic number, because the mean of its divisors is an integer number (902624184).

Almost surely, 2^21321123231 is an apocalyptic number.

21321123231 is a deficient number, since it is larger than the sum of its proper divisors (7562850657).

21321123231 is a wasteful number, since it uses less digits than its factorization.

21321123231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1431.

The product of its digits is 432, while the sum is 21.

Adding to 21321123231 its reverse (13232112312), we get a palindrome (34553235543).

The spelling of 21321123231 in words is "twenty-one billion, three hundred twenty-one million, one hundred twenty-three thousand, two hundred thirty-one".