688536778 has 8 divisors (see below), whose sum is σ = 1040235840. Its totient is φ = 341791500.

The previous prime is 688536743. The next prime is 688536781. The reversal of 688536778 is 877635886.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1238098 + ... + 1238653.

It is an arithmetic number, because the mean of its divisors is an integer number (130029480).

Almost surely, 2^688536778 is an apocalyptic number.

688536778 is a deficient number, since it is larger than the sum of its proper divisors (351699062).

688536778 is a wasteful number, since it uses less digits than its factorization.

688536778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2476892.

The product of its digits is 13547520, while the sum is 58.

The square root of 688536778 is about 26239.9843368856. The cubic root of 688536778 is about 883.0305200888.

The spelling of 688536778 in words is "six hundred eighty-eight million, five hundred thirty-six thousand, seven hundred seventy-eight".