81109404 has 144 divisors (see below), whose sum is σ = 234124800. Its totient is φ = 24204096.

The previous prime is 81109403. The next prime is 81109409. The reversal of 81109404 is 40490118.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81109403) 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 47 ways as a sum of consecutive naturals, for example, 1725709 + ... + 1725755.

Almost surely, 2^81109404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81109404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117062400).

81109404 is an abundant number, since it is smaller than the sum of its proper divisors (153015396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81109404 is a wasteful number, since it uses less digits than its factorization.

81109404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81109404 is about 9006.0759490468. The cubic root of 81109404 is about 432.8695832967.

The spelling of 81109404 in words is "eighty-one million, one hundred nine thousand, four hundred four".