21323443213 has 4 divisors (see below), whose sum is σ = 22577763420. Its totient is φ = 20069123008.

The previous prime is 21323443123. The next prime is 21323443241. The reversal of 21323443213 is 31234432312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12362548969 + 8960894244 = 111187^2 + 94662^2 .

It is a cyclic number.

It is not a de Polignac number, because 21323443213 - 2¹⁷ = 21323312141 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 (21323443243) 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, 627160078 + ... + 627160111.

It is an arithmetic number, because the mean of its divisors is an integer number (5644440855).

Almost surely, 2^21323443213 is an apocalyptic number.

It is an amenable number.

21323443213 is a deficient number, since it is larger than the sum of its proper divisors (1254320207).

21323443213 is a wasteful number, since it uses less digits than its factorization.

21323443213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254320206.

The product of its digits is 10368, while the sum is 28.

Adding to 21323443213 its reverse (31234432312), we get a palindrome (52557875525).

The spelling of 21323443213 in words is "twenty-one billion, three hundred twenty-three million, four hundred forty-three thousand, two hundred thirteen".