668635880 has 128 divisors (see below), whose sum is σ = 1713502080. Its totient is φ = 232657920.

The previous prime is 668635873. The next prime is 668635909. The reversal of 668635880 is 88536866.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1090454 + ... + 1091066.

It is an arithmetic number, because the mean of its divisors is an integer number (13386735).

Almost surely, 2^668635880 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 668635880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (856751040).

668635880 is an abundant number, since it is smaller than the sum of its proper divisors (1044866200).

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

668635880 is a wasteful number, since it uses less digits than its factorization.

668635880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 739 (or 735 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 50.

The square root of 668635880 is about 25857.9945084687. The cubic root of 668635880 is about 874.4397523799.

The spelling of 668635880 in words is "six hundred sixty-eight million, six hundred thirty-five thousand, eight hundred eighty".