216167778 has 20 divisors (see below), whose sum is σ = 484376310. Its totient is φ = 72055872.

The previous prime is 216167759. The next prime is 216167789. The reversal of 216167778 is 877761612.

216167778 is a `hidden beast` number, since 21 + 616 + 7 + 7 + 7 + 8 = 666.

216167778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 214417449 + 1750329 = 14643^2 + 1323^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 667023 + ... + 667346.

Almost surely, 2^216167778 is an apocalyptic number.

216167778 is an abundant number, since it is smaller than the sum of its proper divisors (268208532).

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

216167778 is a wasteful number, since it uses less digits than its factorization.

216167778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1334383 (or 1334374 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The square root of 216167778 is about 14702.6452721951. The cubic root of 216167778 is about 600.1553097946.

The spelling of 216167778 in words is "two hundred sixteen million, one hundred sixty-seven thousand, seven hundred seventy-eight".