66685618 has 16 divisors (see below), whose sum is σ = 103345560. Its totient is φ = 32247936.

The previous prime is 66685609. The next prime is 66685631. The reversal of 66685618 is 81658666.

It can be written as a sum of positive squares in 4 ways, for example, as 56655729 + 10029889 = 7527^2 + 3167^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10198 + ... + 15406.

Almost surely, 2^66685618 is an apocalyptic number.

66685618 is a deficient number, since it is larger than the sum of its proper divisors (36659942).

66685618 is a wasteful number, since it uses less digits than its factorization.

66685618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5421.

The product of its digits is 414720, while the sum is 46.

The square root of 66685618 is about 8166.1262542285. The cubic root of 66685618 is about 405.5185513439.

The spelling of 66685618 in words is "sixty-six million, six hundred eighty-five thousand, six hundred eighteen".