81638883618 has 16 divisors (see below), whose sum is σ = 167690680320. Its totient is φ = 26477475696.

The previous prime is 81638883589. The next prime is 81638883629.

81638883618 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 183871138 + ... + 183871581.

It is an arithmetic number, because the mean of its divisors is an integer number (10480667520).

Almost surely, 2^81638883618 is an apocalyptic number.

81638883618 is an abundant number, since it is smaller than the sum of its proper divisors (86051796702).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81638883618 is a wasteful number, since it uses less digits than its factorization.

81638883618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367742761.

The product of its digits is 10616832, while the sum is 60.

The spelling of 81638883618 in words is "eighty-one billion, six hundred thirty-eight million, eight hundred eighty-three thousand, six hundred eighteen".