21323023213 has 4 divisors (see below), whose sum is σ = 21323537920. Its totient is φ = 21322508508.

The previous prime is 21323023199. The next prime is 21323023219. The reversal of 21323023213 is 31232032312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21323023213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323023219) 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, 189195 + ... + 280072.

It is an arithmetic number, because the mean of its divisors is an integer number (5330884480).

Almost surely, 2^21323023213 is an apocalyptic number.

It is an amenable number.

21323023213 is a deficient number, since it is larger than the sum of its proper divisors (514707).

21323023213 is an equidigital number, since it uses as much as digits as its factorization.

21323023213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514706.

The product of its (nonzero) digits is 1296, while the sum is 22.

Adding to 21323023213 its reverse (31232032312), we get a palindrome (52555055525).

Subtracting 21323023213 from its reverse (31232032312), we obtain a palindrome (9909009099).

The spelling of 21323023213 in words is "twenty-one billion, three hundred twenty-three million, twenty-three thousand, two hundred thirteen".