645556618 has 16 divisors (see below), whose sum is σ = 1107437184. Its totient is φ = 276474960.

The previous prime is 645556607. The next prime is 645556619. The reversal of 645556618 is 816655546.

645556618 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (645556619) 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, 5896 + ... + 36412.

It is an arithmetic number, because the mean of its divisors is an integer number (69214824).

Almost surely, 2^645556618 is an apocalyptic number.

645556618 is a deficient number, since it is larger than the sum of its proper divisors (461880566).

645556618 is a wasteful number, since it uses less digits than its factorization.

645556618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32037.

The product of its digits is 864000, while the sum is 46.

The square root of 645556618 is about 25407.8062413897. The cubic root of 645556618 is about 864.2607282469.

The spelling of 645556618 in words is "six hundred forty-five million, five hundred fifty-six thousand, six hundred eighteen".