81992398816 has 36 divisors (see below), whose sum is σ = 162430605288. Its totient is φ = 40740309632.

The previous prime is 81992398801. The next prime is 81992398819. The reversal of 81992398816 is 61889329918.

It is a Smith number, since the sum of its digits (64) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81992398819) 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 5 ways as a sum of consecutive naturals, for example, 20930490 + ... + 20934406.

It is an arithmetic number, because the mean of its divisors is an integer number (4511961258).

Almost surely, 2^81992398816 is an apocalyptic number.

It is an amenable number.

81992398816 is a deficient number, since it is larger than the sum of its proper divisors (80438206472).

81992398816 is an frugal number, since it uses more digits than its factorization.

81992398816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8011 (or 4086 counting only the distinct ones).

The product of its digits is 13436928, while the sum is 64.

The spelling of 81992398816 in words is "eighty-one billion, nine hundred ninety-two million, three hundred ninety-eight thousand, eight hundred sixteen".