81668966986618 has 16 divisors (see below), whose sum is σ = 133640275697280. Its totient is φ = 37122216637600.

The previous prime is 81668966986577. The next prime is 81668966986619.

81668966986618 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×81668966986618³ (a number of 43 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (81668966986619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28137198 + ... + 30903718.

It is an arithmetic number, because the mean of its divisors is an integer number (8352517231080).

Almost surely, 2^{81668966986618} is an apocalyptic number.

81668966986618 is a deficient number, since it is larger than the sum of its proper divisors (51971308710662).

81668966986618 is a wasteful number, since it uses less digits than its factorization.

81668966986618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4108373.

The product of its digits is 15479341056, while the sum is 88.

The spelling of 81668966986618 in words is "eighty-one trillion, six hundred sixty-eight billion, nine hundred sixty-six million, nine hundred eighty-six thousand, six hundred eighteen".