81383544 has 96 divisors (see below), whose sum is σ = 242087040. Its totient is φ = 24494400.

The previous prime is 81383543. The next prime is 81383569. The reversal of 81383544 is 44538318.

81383544 is a `hidden beast` number, since 81 + 38 + 3 + 544 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 81383499 and 81383508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81383543) 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 23 ways as a sum of consecutive naturals, for example, 166869 + ... + 167355.

It is an arithmetic number, because the mean of its divisors is an integer number (2521740).

Almost surely, 2^81383544 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 81383544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121043520).

81383544 is an abundant number, since it is smaller than the sum of its proper divisors (160703496).

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

81383544 is a wasteful number, since it uses less digits than its factorization.

81383544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721 (or 714 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 81383544 is about 9021.2828356060. The cubic root of 81383544 is about 433.3567172128.

The spelling of 81383544 in words is "eighty-one million, three hundred eighty-three thousand, five hundred forty-four".