21131123321 has 16 divisors (see below), whose sum is σ = 26377387008. Its totient is φ = 16445754000.

The previous prime is 21131123297. The next prime is 21131123327. The reversal of 21131123321 is 12332113112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21131123321 - 2¹⁰ = 21131122297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21131123293 and 21131123302.

It is not an unprimeable number, because it can be changed into a prime (21131123327) 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 15 ways as a sum of consecutive naturals, for example, 103355 + ... + 230096.

It is an arithmetic number, because the mean of its divisors is an integer number (1648586688).

Almost surely, 2^21131123321 is an apocalyptic number.

It is an amenable number.

21131123321 is a deficient number, since it is larger than the sum of its proper divisors (5246263687).

21131123321 is a wasteful number, since it uses less digits than its factorization.

21131123321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334292.

The product of its digits is 216, while the sum is 20.

Adding to 21131123321 its reverse (12332113112), we get a palindrome (33463236433).

The spelling of 21131123321 in words is "twenty-one billion, one hundred thirty-one million, one hundred twenty-three thousand, three hundred twenty-one".