21020332321 has 4 divisors (see below), whose sum is σ = 21376609200. Its totient is φ = 20664055444.

The previous prime is 21020332309. The next prime is 21020332331. The reversal of 21020332321 is 12323302012.

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 not a de Polignac number, because 21020332321 - 2⁹ = 21020331809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020332331) 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, 178138351 + ... + 178138468.

It is an arithmetic number, because the mean of its divisors is an integer number (5344152300).

Almost surely, 2^21020332321 is an apocalyptic number.

It is an amenable number.

21020332321 is a deficient number, since it is larger than the sum of its proper divisors (356276879).

21020332321 is an equidigital number, since it uses as much as digits as its factorization.

21020332321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356276878.

The product of its (nonzero) digits is 432, while the sum is 19.

Adding to 21020332321 its reverse (12323302012), we get a palindrome (33343634333).

The spelling of 21020332321 in words is "twenty-one billion, twenty million, three hundred thirty-two thousand, three hundred twenty-one".