216806555 has 16 divisors (see below), whose sum is σ = 299311104. Its totient is φ = 147679200.

The previous prime is 216806531. The next prime is 216806561. The reversal of 216806555 is 555608612.

It is not a de Polignac number, because 216806555 - 2⁸ = 216806299 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15227 + ... + 25796.

It is an arithmetic number, because the mean of its divisors is an integer number (18706944).

Almost surely, 2^216806555 is an apocalyptic number.

216806555 is a deficient number, since it is larger than the sum of its proper divisors (82504549).

216806555 is a wasteful number, since it uses less digits than its factorization.

216806555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41186.

The product of its (nonzero) digits is 72000, while the sum is 38.

The square root of 216806555 is about 14724.3524475611. The cubic root of 216806555 is about 600.7458825663.

The spelling of 216806555 in words is "two hundred sixteen million, eight hundred six thousand, five hundred fifty-five".