216564557 has 8 divisors (see below), whose sum is σ = 237196512. Its totient is φ = 196090000.

The previous prime is 216564553. The next prime is 216564559. The reversal of 216564557 is 755465612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216564557 - 2² = 216564553 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 (216564553) 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 7 ways as a sum of consecutive naturals, for example, 36458 + ... + 41979.

It is an arithmetic number, because the mean of its divisors is an integer number (29649564).

Almost surely, 2^216564557 is an apocalyptic number.

It is an amenable number.

216564557 is a deficient number, since it is larger than the sum of its proper divisors (20631955).

216564557 is a wasteful number, since it uses less digits than its factorization.

216564557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78699.

The product of its digits is 252000, while the sum is 41.

The square root of 216564557 is about 14716.1325422137. The cubic root of 216564557 is about 600.5222831981.

The spelling of 216564557 in words is "two hundred sixteen million, five hundred sixty-four thousand, five hundred fifty-seven".