81804384 has 96 divisors (see below), whose sum is σ = 242051040. Its totient is φ = 26873856.

The previous prime is 81804377. The next prime is 81804403. The reversal of 81804384 is 48340818.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62424 + ... + 63720.

It is an arithmetic number, because the mean of its divisors is an integer number (2521365).

Almost surely, 2^81804384 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 81804384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121025520).

81804384 is an abundant number, since it is smaller than the sum of its proper divisors (160246656).

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

81804384 is a wasteful number, since it uses less digits than its factorization.

81804384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1389 (or 1375 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 81804384 is about 9044.5776020774. The cubic root of 81804384 is about 434.1024059845.

The spelling of 81804384 in words is "eighty-one million, eight hundred four thousand, three hundred eighty-four".