81338544 has 240 divisors, whose sum is σ = 284743680. Its totient is φ = 21150720.

The previous prime is 81338539. The next prime is 81338561. The reversal of 81338544 is 44583318.

81338544 is a `hidden beast` number, since 81 + 3 + 38 + 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 = 81338499 and 81338508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 593644 + ... + 593780.

It is an arithmetic number, because the mean of its divisors is an integer number (1186432).

Almost surely, 2^81338544 is an apocalyptic number.

81338544 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81338544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142371840).

81338544 is an abundant number, since it is smaller than the sum of its proper divisors (203405136).

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

81338544 is a wasteful number, since it uses less digits than its factorization.

81338544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208 (or 199 counting only the distinct ones).

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

The square root of 81338544 is about 9018.7883886917. The cubic root of 81338544 is about 433.2768294505.

The spelling of 81338544 in words is "eighty-one million, three hundred thirty-eight thousand, five hundred forty-four".