81188811 has 20 divisors (see below), whose sum is σ = 132309144. Its totient is φ = 49204800.

The previous prime is 81188741. The next prime is 81188819. The reversal of 81188811 is 11888118.

81188811 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

It is not a de Polignac number, because 81188811 - 2⁷ = 81188683 is a prime.

81188811 is a modest number, since divided by 188811 gives 81 as remainder.

It is not an unprimeable number, because it can be changed into a prime (81188819) 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 19 ways as a sum of consecutive naturals, for example, 44670 + ... + 46451.

Almost surely, 2^81188811 is an apocalyptic number.

81188811 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81188811 is a deficient number, since it is larger than the sum of its proper divisors (51120333).

81188811 is a wasteful number, since it uses less digits than its factorization.

81188811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91144 (or 91135 counting only the distinct ones).

The product of its digits is 4096, while the sum is 36.

The square root of 81188811 is about 9010.4833943579. The cubic root of 81188811 is about 433.0107985864.

The spelling of 81188811 in words is "eighty-one million, one hundred eighty-eight thousand, eight hundred eleven".