216566111 has 4 divisors (see below), whose sum is σ = 229305312. Its totient is φ = 203826912.

The previous prime is 216566099. The next prime is 216566131. The reversal of 216566111 is 111665612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216566111 - 2¹⁰ = 216565087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216566131) 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, 6369575 + ... + 6369608.

It is an arithmetic number, because the mean of its divisors is an integer number (57326328).

Almost surely, 2^216566111 is an apocalyptic number.

216566111 is a deficient number, since it is larger than the sum of its proper divisors (12739201).

216566111 is a wasteful number, since it uses less digits than its factorization.

216566111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12739200.

The product of its digits is 2160, while the sum is 29.

The square root of 216566111 is about 14716.1853413172. The cubic root of 216566111 is about 600.5237195818.

The spelling of 216566111 in words is "two hundred sixteen million, five hundred sixty-six thousand, one hundred eleven".