778686868 has 6 divisors (see below), whose sum is σ = 1362702026. Its totient is φ = 389343432.

The previous prime is 778686863. The next prime is 778686869. The reversal of 778686868 is 868686877.

778686868 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., 774954244 + 3732624 = 27838^2 + 1932^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (778686863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97335855 + ... + 97335862.

Almost surely, 2^778686868 is an apocalyptic number.

It is an amenable number.

778686868 is a deficient number, since it is larger than the sum of its proper divisors (584015158).

778686868 is a wasteful number, since it uses less digits than its factorization.

778686868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194671721 (or 194671719 counting only the distinct ones).

The product of its digits is 43352064, while the sum is 64.

The square root of 778686868 is about 27904.9613509856. The cubic root of 778686868 is about 919.9995541901. Note that the first 3 decimals are identical.

Subtracting 778686868 from its reverse (868686877), we obtain a palindrome (90000009).

The spelling of 778686868 in words is "seven hundred seventy-eight million, six hundred eighty-six thousand, eight hundred sixty-eight".