216565889 has 2 divisors, whose sum is σ = 216565890. Its totient is φ = 216565888.

The previous prime is 216565883. The next prime is 216565913. The reversal of 216565889 is 988565612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202578289 + 13987600 = 14233^2 + 3740^2 .

It is a cyclic number.

It is not a de Polignac number, because 216565889 - 2¹⁶ = 216500353 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216565883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108282944 + 108282945.

It is an arithmetic number, because the mean of its divisors is an integer number (108282945).

Almost surely, 2^216565889 is an apocalyptic number.

It is an amenable number.

216565889 is a deficient number, since it is larger than the sum of its proper divisors (1).

216565889 is an equidigital number, since it uses as much as digits as its factorization.

216565889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1036800, while the sum is 50.

The square root of 216565889 is about 14716.1777985997. The cubic root of 216565889 is about 600.5235143846.

The spelling of 216565889 in words is "two hundred sixteen million, five hundred sixty-five thousand, eight hundred eighty-nine".