81544665328 has 40 divisors (see below), whose sum is σ = 180839863008. Its totient is φ = 34894163712.

The previous prime is 81544665311. The next prime is 81544665347. The reversal of 81544665328 is 82356644518.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 484351 + ... + 630622.

Almost surely, 2^81544665328 is an apocalyptic number.

It is an amenable number.

81544665328 is an abundant number, since it is smaller than the sum of its proper divisors (99295197680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81544665328 is a wasteful number, since it uses less digits than its factorization.

81544665328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1115641 (or 1115635 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 52.

The spelling of 81544665328 in words is "eighty-one billion, five hundred forty-four million, six hundred sixty-five thousand, three hundred twenty-eight".