668851781776 has 80 divisors (see below), whose sum is σ = 1346249548800. Its totient is φ = 321532198400.

The previous prime is 668851781761. The next prime is 668851781777. The reversal of 668851781776 is 677187158866.

It is not an unprimeable number, because it can be changed into a prime (668851781777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207651846 + ... + 207655066.

It is an arithmetic number, because the mean of its divisors is an integer number (16828119360).

Almost surely, 2^668851781776 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 668851781776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (673124774400).

668851781776 is an abundant number, since it is smaller than the sum of its proper divisors (677397767024).

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

668851781776 is a wasteful number, since it uses less digits than its factorization.

668851781776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5008 (or 5002 counting only the distinct ones).

The product of its digits is 189665280, while the sum is 70.

The spelling of 668851781776 in words is "six hundred sixty-eight billion, eight hundred fifty-one million, seven hundred eighty-one thousand, seven hundred seventy-six".