81936885 has 16 divisors (see below), whose sum is σ = 131340096. Its totient is φ = 43619328.

The previous prime is 81936851. The next prime is 81936893. The reversal of 81936885 is 58863918.

It is not a de Polignac number, because 81936885 - 2¹¹ = 81934837 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 3922 + ... + 13388.

It is an arithmetic number, because the mean of its divisors is an integer number (8208756).

Almost surely, 2^81936885 is an apocalyptic number.

It is an amenable number.

81936885 is a deficient number, since it is larger than the sum of its proper divisors (49403211).

81936885 is a wasteful number, since it uses less digits than its factorization.

81936885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10052.

The product of its digits is 414720, while the sum is 48.

The square root of 81936885 is about 9051.8995244092. The cubic root of 81936885 is about 434.3366557599.

The spelling of 81936885 in words is "eighty-one million, nine hundred thirty-six thousand, eight hundred eighty-five".