668626866 has 64 divisors (see below), whose sum is σ = 1529088000. Its totient is φ = 216448848.

The previous prime is 668626807. The next prime is 668626867.

668626866 is a `hidden beast` number, since 6 + 6 + 8 + 626 + 8 + 6 + 6 = 666.

668626866 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (668626867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 461355 + ... + 462801.

It is an arithmetic number, because the mean of its divisors is an integer number (23892000).

Almost surely, 2^668626866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668626866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (764544000).

668626866 is an abundant number, since it is smaller than the sum of its proper divisors (860461134).

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

668626866 is a wasteful number, since it uses less digits than its factorization.

668626866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1700 (or 1694 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 54.

The square root of 668626866 is about 25857.8202097547. The cubic root of 668626866 is about 874.4358228693.

The spelling of 668626866 in words is "six hundred sixty-eight million, six hundred twenty-six thousand, eight hundred sixty-six".