16320320021 has 2 divisors, whose sum is σ = 16320320022. Its totient is φ = 16320320020.

The previous prime is 16320320011. The next prime is 16320320077. The reversal of 16320320021 is 12002302361.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13089648100 + 3230671921 = 114410^2 + 56839^2 .

It is a cyclic number.

It is not a de Polignac number, because 16320320021 - 2¹⁸ = 16320057877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16320319975 and 16320320002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16320320011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8160160010 + 8160160011.

It is an arithmetic number, because the mean of its divisors is an integer number (8160160011).

Almost surely, 2^16320320021 is an apocalyptic number.

It is an amenable number.

16320320021 is a deficient number, since it is larger than the sum of its proper divisors (1).

16320320021 is an equidigital number, since it uses as much as digits as its factorization.

16320320021 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 20.

Adding to 16320320021 its reverse (12002302361), we get a palindrome (28322622382).

The spelling of 16320320021 in words is "sixteen billion, three hundred twenty million, three hundred twenty thousand, twenty-one".