216386321 has 2 divisors, whose sum is σ = 216386322. Its totient is φ = 216386320.

The previous prime is 216386309. The next prime is 216386327. The reversal of 216386321 is 123683612.

216386321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202777600 + 13608721 = 14240^2 + 3689^2 .

It is a cyclic number.

It is not a de Polignac number, because 216386321 - 2⁶ = 216386257 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (216386327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108193160 + 108193161.

It is an arithmetic number, because the mean of its divisors is an integer number (108193161).

Almost surely, 2^216386321 is an apocalyptic number.

It is an amenable number.

216386321 is a deficient number, since it is larger than the sum of its proper divisors (1).

216386321 is an equidigital number, since it uses as much as digits as its factorization.

216386321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 32.

The square root of 216386321 is about 14710.0754926683. The cubic root of 216386321 is about 600.3574915869.

The spelling of 216386321 in words is "two hundred sixteen million, three hundred eighty-six thousand, three hundred twenty-one".