81671017618 has 8 divisors (see below), whose sum is σ = 122565232512. Its totient is φ = 40815940116.

The previous prime is 81671017559. The next prime is 81671017651.

It is a happy number.

81671017618 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9779130 + ... + 9787477.

It is an arithmetic number, because the mean of its divisors is an integer number (15320654064).

Almost surely, 2^81671017618 is an apocalyptic number.

81671017618 is a deficient number, since it is larger than the sum of its proper divisors (40894214894).

81671017618 is a wasteful number, since it uses less digits than its factorization.

81671017618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19568696.

The product of its (nonzero) digits is 112896, while the sum is 46.

The spelling of 81671017618 in words is "eighty-one billion, six hundred seventy-one million, seventeen thousand, six hundred eighteen".