21021323223 has 16 divisors (see below), whose sum is σ = 28088856576. Its totient is φ = 13984033440.

The previous prime is 21021323207. The next prime is 21021323233. The reversal of 21021323223 is 32232312012.

It is a happy number.

It is not a de Polignac number, because 21021323223 - 2⁴ = 21021323207 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21021323223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021323233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4284990 + ... + 4289892.

It is an arithmetic number, because the mean of its divisors is an integer number (1755553536).

Almost surely, 2^21021323223 is an apocalyptic number.

21021323223 is a deficient number, since it is larger than the sum of its proper divisors (7067533353).

21021323223 is a wasteful number, since it uses less digits than its factorization.

21021323223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7694.

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 21021323223 its reverse (32232312012), we get a palindrome (53253635235).

The spelling of 21021323223 in words is "twenty-one billion, twenty-one million, three hundred twenty-three thousand, two hundred twenty-three".