81715503747285 has 24 divisors (see below), whose sum is σ = 145468320187320. Its totient is φ = 42403720862592.

The previous prime is 81715503747209. The next prime is 81715503747329. The reversal of 81715503747285 is 58274730551718.

81715503747285 is a `hidden beast` number, since 8 + 1 + 7 + 1 + 5 + 50 + 37 + 472 + 85 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 22645473143076 + 59070030604209 = 4758726^2 + 7685703^2 .

It is not a de Polignac number, because 81715503747285 - 2¹² = 81715503743189 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24539188650 + ... + 24539191979.

It is an arithmetic number, because the mean of its divisors is an integer number (6061180007805).

Almost surely, 2^{81715503747285} is an apocalyptic number.

It is an amenable number.

81715503747285 is a deficient number, since it is larger than the sum of its proper divisors (63752816440035).

81715503747285 is a wasteful number, since it uses less digits than its factorization.

81715503747285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49078380677 (or 49078380674 counting only the distinct ones).

The product of its (nonzero) digits is 65856000, while the sum is 63.

The spelling of 81715503747285 in words is "eighty-one trillion, seven hundred fifteen billion, five hundred three million, seven hundred forty-seven thousand, two hundred eighty-five".