6688937778 has 8 divisors (see below), whose sum is σ = 13377875568. Its totient is φ = 2229645924.

The previous prime is 6688937767. The next prime is 6688937779. The reversal of 6688937778 is 8777398866.

It is a sphenic number, since it is the product of 3 distinct primes.

6688937778 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (6688937779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 557411476 + ... + 557411487.

It is an arithmetic number, because the mean of its divisors is an integer number (1672234446).

Almost surely, 2^6688937778 is an apocalyptic number.

6688937778 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

6688937778 is a wasteful number, since it uses less digits than its factorization.

6688937778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1114822968.

The product of its digits is 170698752, while the sum is 69.

The square root of 6688937778 is about 81785.9265277346. The cubic root of 6688937778 is about 1884.1655201199.

The spelling of 6688937778 in words is "six billion, six hundred eighty-eight million, nine hundred thirty-seven thousand, seven hundred seventy-eight".