81398943859827 has 32 divisors (see below), whose sum is σ = 121599463184640. Its totient is φ = 47998966331520.

The previous prime is 81398943859817. The next prime is 81398943859861. The reversal of 81398943859827 is 72895834989318.

It is not a de Polignac number, because 81398943859827 - 2¹² = 81398943855731 is a prime.

It is a super-2 number, since 2×81398943859827² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81398943859827.

It is not an unprimeable number, because it can be changed into a prime (81398943859817) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 199897749 + ... + 200304537.

It is an arithmetic number, because the mean of its divisors is an integer number (3799983224520).

Almost surely, 2^{81398943859827} is an apocalyptic number.

81398943859827 is a deficient number, since it is larger than the sum of its proper divisors (40200519324813).

81398943859827 is a wasteful number, since it uses less digits than its factorization.

81398943859827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570723.

The product of its digits is 7524679680, while the sum is 84.

The spelling of 81398943859827 in words is "eighty-one trillion, three hundred ninety-eight billion, nine hundred forty-three million, eight hundred fifty-nine thousand, eight hundred twenty-seven".