640943056618 has 16 divisors (see below), whose sum is σ = 987883251840. Its totient is φ = 311657139216.

The previous prime is 640943056613. The next prime is 640943056627. The reversal of 640943056618 is 816650349046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640943056613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1973046 + ... + 2274817.

It is an arithmetic number, because the mean of its divisors is an integer number (61742703240).

Almost surely, 2^640943056618 is an apocalyptic number.

640943056618 is a deficient number, since it is larger than the sum of its proper divisors (346940195222).

640943056618 is a wasteful number, since it uses less digits than its factorization.

640943056618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4249941.

The product of its (nonzero) digits is 3732480, while the sum is 52.

The spelling of 640943056618 in words is "six hundred forty billion, nine hundred forty-three million, fifty-six thousand, six hundred eighteen".