21020023223 has 4 divisors (see below), whose sum is σ = 21744851640. Its totient is φ = 20295194808.

The previous prime is 21020023187. The next prime is 21020023237. The reversal of 21020023223 is 32232002012.

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

It is a cyclic number.

It is not a de Polignac number, because 21020023223 - 2¹⁶ = 21019957687 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 (21020023243) 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, 362414165 + ... + 362414222.

It is an arithmetic number, because the mean of its divisors is an integer number (5436212910).

Almost surely, 2^21020023223 is an apocalyptic number.

21020023223 is a deficient number, since it is larger than the sum of its proper divisors (724828417).

21020023223 is an equidigital number, since it uses as much as digits as its factorization.

21020023223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724828416.

The product of its (nonzero) digits is 288, while the sum is 17.

Adding to 21020023223 its reverse (32232002012), we get a palindrome (53252025235).

The spelling of 21020023223 in words is "twenty-one billion, twenty million, twenty-three thousand, two hundred twenty-three".