81081248085 has 12 divisors (see below), whose sum is σ = 140540830092. Its totient is φ = 43243332288.

The previous prime is 81081247981. The next prime is 81081248089. The reversal of 81081248085 is 58084218018.

81081248085 is a `hidden beast` number, since 8 + 10 + 81 + 2 + 480 + 85 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 49109662449 + 31971585636 = 221607^2 + 178806^2 .

It is not a de Polignac number, because 81081248085 - 2⁹ = 81081247573 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 1801805513 = 81081248085 / (8 + 1 + 0 + 8 + 1 + 2 + 4 + 8 + 0 + 8 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 81081248085.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81081248089) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 900902712 + ... + 900902801.

It is an arithmetic number, because the mean of its divisors is an integer number (11711735841).

Almost surely, 2^81081248085 is an apocalyptic number.

It is an amenable number.

81081248085 is a deficient number, since it is larger than the sum of its proper divisors (59459582007).

81081248085 is a wasteful number, since it uses less digits than its factorization.

81081248085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1801805524 (or 1801805521 counting only the distinct ones).

The product of its (nonzero) digits is 163840, while the sum is 45.

The spelling of 81081248085 in words is "eighty-one billion, eighty-one million, two hundred forty-eight thousand, eighty-five".