666388568 has 32 divisors (see below), whose sum is σ = 1318485600. Its totient is φ = 315118848.

The previous prime is 666388543. The next prime is 666388573. The reversal of 666388568 is 865883666.

It is a super-2 number, since 2×666388568² = 888147447122181248, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3971 + ... + 36722.

It is an arithmetic number, because the mean of its divisors is an integer number (41202675).

Almost surely, 2^666388568 is an apocalyptic number.

It is an amenable number.

666388568 is a deficient number, since it is larger than the sum of its proper divisors (652097032).

666388568 is a wasteful number, since it uses less digits than its factorization.

666388568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40811 (or 40807 counting only the distinct ones).

The product of its digits is 9953280, while the sum is 56.

The square root of 666388568 is about 25814.5030554531. The cubic root of 666388568 is about 873.4589770607.

The spelling of 666388568 in words is "six hundred sixty-six million, three hundred eighty-eight thousand, five hundred sixty-eight".