81796765312 has 16 divisors (see below), whose sum is σ = 162954493650. Its totient is φ = 40898382592.

The previous prime is 81796765289. The next prime is 81796765313. The reversal of 81796765312 is 21356769718.

It can be written as a sum of positive squares in only one way, i.e., 79086938176 + 2709827136 = 281224^2 + 52056^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81796765313) 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 as a sum of consecutive naturals, namely, 319518487 + ... + 319518742.

Almost surely, 2^81796765312 is an apocalyptic number.

It is an amenable number.

81796765312 is a deficient number, since it is larger than the sum of its proper divisors (81157728338).

81796765312 is an equidigital number, since it uses as much as digits as its factorization.

81796765312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639037243 (or 639037231 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 55.

The spelling of 81796765312 in words is "eighty-one billion, seven hundred ninety-six million, seven hundred sixty-five thousand, three hundred twelve".