81128080 has 180 divisors, whose sum is σ = 227836980. Its totient is φ = 26808320.

The previous prime is 81128077. The next prime is 81128093. The reversal of 81128080 is 8082118.

It can be written as a sum of positive squares in 6 ways, for example, as 4460544 + 76667536 = 2112^2 + 8756^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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 35 ways as a sum of consecutive naturals, for example, 2797506 + ... + 2797534.

It is an arithmetic number, because the mean of its divisors is an integer number (1265761).

Almost surely, 2^81128080 is an apocalyptic number.

81128080 is a gapful number since it is divisible by the number (80) 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 81128080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113918490).

81128080 is an abundant number, since it is smaller than the sum of its proper divisors (146708900).

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

81128080 is a wasteful number, since it uses less digits than its factorization.

81128080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 28.

The square root of 81128080 is about 9007.1127449366. The cubic root of 81128080 is about 432.9028044833.

The spelling of 81128080 in words is "eighty-one million, one hundred twenty-eight thousand, eighty".