78550866 has 24 divisors (see below), whose sum is σ = 172109340. Its totient is φ = 25888896.

The previous prime is 78550861. The next prime is 78550873. The reversal of 78550866 is 66805587.

78550866 is a `hidden beast` number, since 7 + 85 + 508 + 66 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 70308225 + 8242641 = 8385^2 + 2871^2 .

It is not an unprimeable number, because it can be changed into a prime (78550861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22915 + ... + 26118.

Almost surely, 2^78550866 is an apocalyptic number.

78550866 is an abundant number, since it is smaller than the sum of its proper divisors (93558474).

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

78550866 is a wasteful number, since it uses less digits than its factorization.

78550866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49130 (or 49127 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The square root of 78550866 is about 8862.8926429242. The cubic root of 78550866 is about 428.2693481750.

The spelling of 78550866 in words is "seventy-eight million, five hundred fifty thousand, eight hundred sixty-six".