216566317 has 4 divisors (see below), whose sum is σ = 236254176. Its totient is φ = 196878460.

The previous prime is 216566299. The next prime is 216566353. The reversal of 216566317 is 713665612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216566317 - 2²³ = 208177709 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 (216566377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9843913 + ... + 9843934.

It is an arithmetic number, because the mean of its divisors is an integer number (59063544).

Almost surely, 2^216566317 is an apocalyptic number.

It is an amenable number.

216566317 is a deficient number, since it is larger than the sum of its proper divisors (19687859).

216566317 is a wasteful number, since it uses less digits than its factorization.

216566317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19687858.

The product of its digits is 45360, while the sum is 37.

The square root of 216566317 is about 14716.1923404120. The cubic root of 216566317 is about 600.5239099900.

The spelling of 216566317 in words is "two hundred sixteen million, five hundred sixty-six thousand, three hundred seventeen".