216688555 has 16 divisors (see below), whose sum is σ = 262603584. Its totient is φ = 171642240.

The previous prime is 216688553. The next prime is 216688561. The reversal of 216688555 is 555886612.

It is a happy number.

It is not a de Polignac number, because 216688555 - 2¹ = 216688553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216688553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 343090 + ... + 343720.

It is an arithmetic number, because the mean of its divisors is an integer number (16412724).

Almost surely, 2^216688555 is an apocalyptic number.

216688555 is a deficient number, since it is larger than the sum of its proper divisors (45915029).

216688555 is a wasteful number, since it uses less digits than its factorization.

216688555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206.

The product of its digits is 576000, while the sum is 46.

The square root of 216688555 is about 14720.3449348173. The cubic root of 216688555 is about 600.6368746712.

The spelling of 216688555 in words is "two hundred sixteen million, six hundred eighty-eight thousand, five hundred fifty-five".