216564555 has 32 divisors (see below), whose sum is σ = 359631360. Its totient is φ = 111202560.

The previous prime is 216564553. The next prime is 216564559. The reversal of 216564555 is 555465612.

It is a happy number.

It is not a de Polignac number, because 216564555 - 2¹ = 216564553 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 43431 + ... + 48159.

It is an arithmetic number, because the mean of its divisors is an integer number (11238480).

Almost surely, 2^216564555 is an apocalyptic number.

216564555 is a deficient number, since it is larger than the sum of its proper divisors (143066805).

216564555 is a wasteful number, since it uses less digits than its factorization.

216564555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4851.

The product of its digits is 180000, while the sum is 39.

The square root of 216564555 is about 14716.1324742610. The cubic root of 216564555 is about 600.5222813495.

The spelling of 216564555 in words is "two hundred sixteen million, five hundred sixty-four thousand, five hundred fifty-five".