21231211323 has 24 divisors (see below), whose sum is σ = 32964813648. Its totient is φ = 12119310336.

The previous prime is 21231211307. The next prime is 21231211349. The reversal of 21231211323 is 32311213212.

It is not a de Polignac number, because 21231211323 - 2⁴ = 21231211307 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21231211323.

It is not an unprimeable number, because it can be changed into a prime (21231211123) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64315 + ... + 215867.

It is an arithmetic number, because the mean of its divisors is an integer number (1373533902).

Almost surely, 2^21231211323 is an apocalyptic number.

21231211323 is a deficient number, since it is larger than the sum of its proper divisors (11733602325).

21231211323 is a wasteful number, since it uses less digits than its factorization.

21231211323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152523 (or 152516 counting only the distinct ones).

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

Adding to 21231211323 its reverse (32311213212), we get a palindrome (53542424535).

The spelling of 21231211323 in words is "twenty-one billion, two hundred thirty-one million, two hundred eleven thousand, three hundred twenty-three".