21320332021 has 2 divisors, whose sum is σ = 21320332022. Its totient is φ = 21320332020.

The previous prime is 21320331997. The next prime is 21320332049. The reversal of 21320332021 is 12023302312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19457460100 + 1862871921 = 139490^2 + 43161^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320332021 - 2²⁹ = 20783461109 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21320332021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21320332081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660166010 + 10660166011.

It is an arithmetic number, because the mean of its divisors is an integer number (10660166011).

Almost surely, 2^21320332021 is an apocalyptic number.

It is an amenable number.

21320332021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320332021 is an equidigital number, since it uses as much as digits as its factorization.

21320332021 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21320332021 its reverse (12023302312), we get a palindrome (33343634333).

The spelling of 21320332021 in words is "twenty-one billion, three hundred twenty million, three hundred thirty-two thousand, twenty-one".