216091816 has 8 divisors (see below), whose sum is σ = 405172170. Its totient is φ = 108045904.

The previous prime is 216091787. The next prime is 216091849. The reversal of 216091816 is 618190612.

It can be written as a sum of positive squares in only one way, i.e., 199656900 + 16434916 = 14130^2 + 4054^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13505731 + ... + 13505746.

Almost surely, 2^216091816 is an apocalyptic number.

It is an amenable number.

216091816 is a deficient number, since it is larger than the sum of its proper divisors (189080354).

216091816 is a wasteful number, since it uses less digits than its factorization.

216091816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27011483 (or 27011479 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 216091816 is about 14700.0617685777. The cubic root of 216091816 is about 600.0850027718.

The spelling of 216091816 in words is "two hundred sixteen million, ninety-one thousand, eight hundred sixteen".