668578618 has 16 divisors (see below), whose sum is σ = 1063039464. Its totient is φ = 314275840.

The previous prime is 668578613. The next prime is 668578627. The reversal of 668578618 is 816875866.

It can be written as a sum of positive squares in 4 ways, for example, as 656025769 + 12552849 = 25613^2 + 3543^2 .

It is not an unprimeable number, because it can be changed into a prime (668578613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21546 + ... + 42442.

Almost surely, 2^668578618 is an apocalyptic number.

668578618 is a deficient number, since it is larger than the sum of its proper divisors (394460846).

668578618 is a wasteful number, since it uses less digits than its factorization.

668578618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21857.

The product of its digits is 3870720, while the sum is 55.

The square root of 668578618 is about 25856.8872449876. The cubic root of 668578618 is about 874.4147893171.

The spelling of 668578618 in words is "six hundred sixty-eight million, five hundred seventy-eight thousand, six hundred eighteen".