668383640 has 64 divisors (see below), whose sum is σ = 1555092000. Its totient is φ = 258370560.

The previous prime is 668383627. The next prime is 668383717. The reversal of 668383640 is 46383866.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 668383591 and 668383600.

It is a congruent number.

It is an unprimeable number.

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, 176891 + ... + 180629.

Almost surely, 2^668383640 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 668383640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (777546000).

668383640 is an abundant number, since it is smaller than the sum of its proper divisors (886708360).

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

668383640 is a wasteful number, since it uses less digits than its factorization.

668383640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3900 (or 3896 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 44.

The square root of 668383640 is about 25853.1166399721. The cubic root of 668383640 is about 874.3297790089.

The spelling of 668383640 in words is "six hundred sixty-eight million, three hundred eighty-three thousand, six hundred forty".