81801109 has 16 divisors (see below), whose sum is σ = 90881280. Its totient is φ = 73146240.

The previous prime is 81801107. The next prime is 81801143. The reversal of 81801109 is 90110818.

It is a cyclic number.

It is not a de Polignac number, because 81801109 - 2¹ = 81801107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81801107) by changing a digit.

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, 88552 + ... + 89470.

It is an arithmetic number, because the mean of its divisors is an integer number (5680080).

Almost surely, 2^81801109 is an apocalyptic number.

It is an amenable number.

81801109 is a deficient number, since it is larger than the sum of its proper divisors (9080171).

81801109 is a wasteful number, since it uses less digits than its factorization.

81801109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1140.

The product of its (nonzero) digits is 576, while the sum is 28.

The square root of 81801109 is about 9044.3965525623. The cubic root of 81801109 is about 434.0966128787.

The spelling of 81801109 in words is "eighty-one million, eight hundred one thousand, one hundred nine".