81643996048 has 20 divisors (see below), whose sum is σ = 158523983280. Its totient is φ = 40734581024.

The previous prime is 81643996043. The next prime is 81643996067. The reversal of 81643996048 is 84069934618.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81643995983 and 81643996001.

It is not an unprimeable number, because it can be changed into a prime (81643996043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5455858 + ... + 5470801.

It is an arithmetic number, because the mean of its divisors is an integer number (7926199164).

Almost surely, 2^81643996048 is an apocalyptic number.

It is an amenable number.

81643996048 is a deficient number, since it is larger than the sum of its proper divisors (76879987232).

81643996048 is a wasteful number, since it uses less digits than its factorization.

81643996048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10927134 (or 10927128 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 58.

The spelling of 81643996048 in words is "eighty-one billion, six hundred forty-three million, nine hundred ninety-six thousand, forty-eight".