81686068618 has 32 divisors (see below), whose sum is σ = 155043629568. Its totient is φ = 31350726000.

The previous prime is 81686068589. The next prime is 81686068627.

81686068618 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×81686068618² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3948108 + ... + 3968743.

It is an arithmetic number, because the mean of its divisors is an integer number (4845113424).

Almost surely, 2^81686068618 is an apocalyptic number.

81686068618 is a deficient number, since it is larger than the sum of its proper divisors (73357560950).

81686068618 is a wasteful number, since it uses less digits than its factorization.

81686068618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7916938.

The product of its (nonzero) digits is 5308416, while the sum is 58.

The spelling of 81686068618 in words is "eighty-one billion, six hundred eighty-six million, sixty-eight thousand, six hundred eighteen".