640382668 has 12 divisors (see below), whose sum is σ = 1122919000. Its totient is φ = 319548672.

The previous prime is 640382653. The next prime is 640382681. The reversal of 640382668 is 866283046.

It is a super-2 number, since 2×640382668² = 820179922949596448, which contains 22 as substring.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 158421 + ... + 162412.

Almost surely, 2^640382668 is an apocalyptic number.

It is an amenable number.

640382668 is a deficient number, since it is larger than the sum of its proper divisors (482536332).

640382668 is a wasteful number, since it uses less digits than its factorization.

640382668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321336 (or 321334 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 43.

The square root of 640382668 is about 25305.7832915719. The cubic root of 640382668 is about 861.9455987115.

The spelling of 640382668 in words is "six hundred forty million, three hundred eighty-two thousand, six hundred sixty-eight".