81715056 has 80 divisors (see below), whose sum is σ = 224985600. Its totient is φ = 25467904.

The previous prime is 81715033. The next prime is 81715057. The reversal of 81715056 is 65051718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81715057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194815 + ... + 195233.

It is an arithmetic number, because the mean of its divisors is an integer number (2812320).

Almost surely, 2^81715056 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 81715056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112492800).

81715056 is an abundant number, since it is smaller than the sum of its proper divisors (143270544).

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

81715056 is a wasteful number, since it uses less digits than its factorization.

81715056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 680 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 33.

The square root of 81715056 is about 9039.6380458512. The cubic root of 81715056 is about 433.9443393829.

The spelling of 81715056 in words is "eighty-one million, seven hundred fifteen thousand, fifty-six".