216211806 has 12 divisors (see below), whose sum is σ = 468458952. Its totient is φ = 72070596.

The previous prime is 216211777. The next prime is 216211829. The reversal of 216211806 is 608112612.

216211806 is a `hidden beast` number, since 21 + 621 + 18 + 0 + 6 = 666.

216211806 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216211806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6005866 + ... + 6005901.

It is an arithmetic number, because the mean of its divisors is an integer number (39038246).

Almost surely, 2^216211806 is an apocalyptic number.

216211806 is an abundant number, since it is smaller than the sum of its proper divisors (252247146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216211806 is a wasteful number, since it uses less digits than its factorization.

216211806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12011775 (or 12011772 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 216211806 is about 14704.1424775469. The cubic root of 216211806 is about 600.1960525987.

The spelling of 216211806 in words is "two hundred sixteen million, two hundred eleven thousand, eight hundred six".