81128861724 has 48 divisors (see below), whose sum is σ = 195968455200. Its totient is φ = 26091749376.

The previous prime is 81128861717. The next prime is 81128861731. The reversal of 81128861724 is 42716882118.

It is an interprime number because it is at equal distance from previous prime (81128861717) and next prime (81128861731).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 407604 + ... + 573060.

It is an arithmetic number, because the mean of its divisors is an integer number (4082676150).

Almost surely, 2^81128861724 is an apocalyptic number.

It is an amenable number.

81128861724 is an abundant number, since it is smaller than the sum of its proper divisors (114839593476).

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

81128861724 is a wasteful number, since it uses less digits than its factorization.

81128861724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166902 (or 166900 counting only the distinct ones).

The product of its digits is 344064, while the sum is 48.

The spelling of 81128861724 in words is "eighty-one billion, one hundred twenty-eight million, eight hundred sixty-one thousand, seven hundred twenty-four".