81128842 has 8 divisors (see below), whose sum is σ = 123360516. Its totient is φ = 40008672.

The previous prime is 81128837. The next prime is 81128857. The reversal of 81128842 is 24882118.

It can be written as a sum of positive squares in 2 ways, for example, as 76930441 + 4198401 = 8771^2 + 2049^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 81128798 and 81128807.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 277693 + ... + 277984.

Almost surely, 2^81128842 is an apocalyptic number.

81128842 is a deficient number, since it is larger than the sum of its proper divisors (42231674).

81128842 is a wasteful number, since it uses less digits than its factorization.

81128842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555752.

The product of its digits is 8192, while the sum is 34.

The square root of 81128842 is about 9007.1550447408. The cubic root of 81128842 is about 432.9041598336.

The spelling of 81128842 in words is "eighty-one million, one hundred twenty-eight thousand, eight hundred forty-two".