81725443128 has 576 divisors, whose sum is σ = 289089216000. Its totient is φ = 21117811968.

The previous prime is 81725443099. The next prime is 81725443133. The reversal of 81725443128 is 82134452718.

81725443128 is a `hidden beast` number, since 8 + 1 + 72 + 544 + 31 + 2 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

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 in 143 ways as a sum of consecutive naturals, for example, 160560538 + ... + 160561046.

It is an arithmetic number, because the mean of its divisors is an integer number (501891000).

Almost surely, 2^81725443128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81725443128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144544608000).

81725443128 is an abundant number, since it is smaller than the sum of its proper divisors (207363772872).

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

81725443128 is a wasteful number, since it uses less digits than its factorization.

81725443128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 588 (or 563 counting only the distinct ones).

The product of its digits is 430080, while the sum is 45.

The spelling of 81725443128 in words is "eighty-one billion, seven hundred twenty-five million, four hundred forty-three thousand, one hundred twenty-eight".