81823385 has 12 divisors (see below), whose sum is σ = 114219108. Its totient is φ = 56107296.

The previous prime is 81823369. The next prime is 81823393. The reversal of 81823385 is 58332818.

It can be written as a sum of positive squares in 2 ways, for example, as 12201049 + 69622336 = 3493^2 + 8344^2 .

It is not a de Polignac number, because 81823385 - 2⁴ = 81823369 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166742 + ... + 167231.

It is an arithmetic number, because the mean of its divisors is an integer number (9518259).

Almost surely, 2^81823385 is an apocalyptic number.

It is an amenable number.

81823385 is a deficient number, since it is larger than the sum of its proper divisors (32395723).

81823385 is a wasteful number, since it uses less digits than its factorization.

81823385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333992 (or 333985 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 81823385 is about 9045.6279494571. The cubic root of 81823385 is about 434.1360135610.

The spelling of 81823385 in words is "eighty-one million, eight hundred twenty-three thousand, three hundred eighty-five".