81191683813863 has 32 divisors (see below), whose sum is σ = 125468403886080. Its totient is φ = 45743688345600.

The previous prime is 81191683813853. The next prime is 81191683813897. The reversal of 81191683813863 is 36831838619118.

It is a happy number.

It is not a de Polignac number, because 81191683813863 - 2¹³ = 81191683805671 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81191683813794 and 81191683813803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81191683813853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79576570 + ... + 80590407.

It is an arithmetic number, because the mean of its divisors is an integer number (3920887621440).

Almost surely, 2^{81191683813863} is an apocalyptic number.

81191683813863 is a deficient number, since it is larger than the sum of its proper divisors (44276720072217).

81191683813863 is a wasteful number, since it uses less digits than its factorization.

81191683813863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160167327.

The product of its digits is 35831808, while the sum is 66.

The spelling of 81191683813863 in words is "eighty-one trillion, one hundred ninety-one billion, six hundred eighty-three million, eight hundred thirteen thousand, eight hundred sixty-three".