81855128 has 16 divisors (see below), whose sum is σ = 158429760. Its totient is φ = 39607200.

The previous prime is 81855127. The next prime is 81855131. The reversal of 81855128 is 82155818.

It is a junction number, because it is equal to n+sod(n) for n = 81855091 and 81855100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81855121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164783 + ... + 165278.

It is an arithmetic number, because the mean of its divisors is an integer number (9901860).

Almost surely, 2^81855128 is an apocalyptic number.

It is an amenable number.

81855128 is a deficient number, since it is larger than the sum of its proper divisors (76574632).

81855128 is a wasteful number, since it uses less digits than its factorization.

81855128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330098 (or 330094 counting only the distinct ones).

The product of its digits is 25600, while the sum is 38.

The square root of 81855128 is about 9047.3823838721. The cubic root of 81855128 is about 434.1921466490.

The spelling of 81855128 in words is "eighty-one million, eight hundred fifty-five thousand, one hundred twenty-eight".