81930774528 has 72 divisors (see below), whose sum is σ = 236631172050. Its totient is φ = 27310252032.

The previous prime is 81930774517. The next prime is 81930774533. The reversal of 81930774528 is 82547703918.

It is a happy number.

81930774528 is a `hidden beast` number, since 8 + 19 + 30 + 7 + 74 + 528 = 666.

It can be written as a sum of positive squares in only one way, i.e., 75225129984 + 6705644544 = 274272^2 + 81888^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 2204083 + ... + 2240946.

Almost surely, 2^81930774528 is an apocalyptic number.

It is an amenable number.

81930774528 is an abundant number, since it is smaller than the sum of its proper divisors (154700397522).

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

81930774528 is a wasteful number, since it uses less digits than its factorization.

81930774528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4445057 (or 4445034 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 54.

The spelling of 81930774528 in words is "eighty-one billion, nine hundred thirty million, seven hundred seventy-four thousand, five hundred twenty-eight".