678640731808 has 72 divisors (see below), whose sum is σ = 1457316465948. Its totient is φ = 310932191232.

The previous prime is 678640731803. The next prime is 678640731827. The reversal of 678640731808 is 808137046876.

It can be written as a sum of positive squares in 6 ways, for example, as 203881147024 + 474759584784 = 451532^2 + 689028^2 .

It is not an unprimeable number, because it can be changed into a prime (678640731803) 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, 282910 + ... + 1198882.

Almost surely, 2^678640731808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 678640731808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (728658232974).

678640731808 is an abundant number, since it is smaller than the sum of its proper divisors (778675734140).

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

678640731808 is a wasteful number, since it uses less digits than its factorization.

678640731808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916146 (or 916125 counting only the distinct ones).

The product of its (nonzero) digits is 10838016, while the sum is 58.

The spelling of 678640731808 in words is "six hundred seventy-eight billion, six hundred forty million, seven hundred thirty-one thousand, eight hundred eight".