81928655424 has 1512 divisors, whose sum is σ = 340763705568. Its totient is φ = 18533007360.

The previous prime is 81928655423. The next prime is 81928655533. The reversal of 81928655424 is 42455682918.

81928655424 is a `hidden beast` number, since 8 + 1 + 9 + 2 + 86 + 554 + 2 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (81928655423) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 1905317547 + ... + 1905317589.

Almost surely, 2^81928655424 is an apocalyptic number.

81928655424 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81928655424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170381852784).

81928655424 is an abundant number, since it is smaller than the sum of its proper divisors (258835050144).

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

81928655424 is a wasteful number, since it uses less digits than its factorization.

81928655424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 102 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 54.

The spelling of 81928655424 in words is "eighty-one billion, nine hundred twenty-eight million, six hundred fifty-five thousand, four hundred twenty-four".