641688538618 has 16 divisors (see below), whose sum is σ = 993825043200. Its totient is φ = 310418582400.

The previous prime is 641688538583. The next prime is 641688538627. The reversal of 641688538618 is 816835886146.

It is a self number, because there is not a number n which added to its sum of digits gives 641688538618.

It is an unprimeable number.

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, 1008343 + ... + 1516618.

It is an arithmetic number, because the mean of its divisors is an integer number (62114065200).

Almost surely, 2^641688538618 is an apocalyptic number.

641688538618 is a deficient number, since it is larger than the sum of its proper divisors (352136504582).

641688538618 is a wasteful number, since it uses less digits than its factorization.

641688538618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2529093.

The product of its digits is 53084160, while the sum is 64.

The spelling of 641688538618 in words is "six hundred forty-one billion, six hundred eighty-eight million, five hundred thirty-eight thousand, six hundred eighteen".