81715872 has 192 divisors, whose sum is σ = 271724544. Its totient is φ = 20951040.

The previous prime is 81715861. The next prime is 81715873. The reversal of 81715872 is 27851718.

It is a self number, because there is not a number n which added to its sum of digits gives 81715872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81715873) 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 31 ways as a sum of consecutive naturals, for example, 262597 + ... + 262907.

It is an arithmetic number, because the mean of its divisors is an integer number (1415232).

Almost surely, 2^81715872 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 81715872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135862272).

81715872 is an abundant number, since it is smaller than the sum of its proper divisors (190008672).

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

81715872 is a wasteful number, since it uses less digits than its factorization.

81715872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371 (or 363 counting only the distinct ones).

The product of its digits is 31360, while the sum is 39.

The square root of 81715872 is about 9039.6831802890. The cubic root of 81715872 is about 433.9457838226.

The spelling of 81715872 in words is "eighty-one million, seven hundred fifteen thousand, eight hundred seventy-two".