81500565715 has 24 divisors (see below), whose sum is σ = 101511538128. Its totient is φ = 62814111360.

The previous prime is 81500565709. The next prime is 81500565737. The reversal of 81500565715 is 51756500518.

It is not a de Polignac number, because 81500565715 - 2²⁹ = 80963694803 is a prime.

It is a super-2 number, since 2×81500565715² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1917484 + ... + 1959526.

It is an arithmetic number, because the mean of its divisors is an integer number (4229647422).

Almost surely, 2^81500565715 is an apocalyptic number.

81500565715 is a deficient number, since it is larger than the sum of its proper divisors (20010972413).

81500565715 is a wasteful number, since it uses less digits than its factorization.

81500565715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42567 (or 42538 counting only the distinct ones).

The product of its (nonzero) digits is 210000, while the sum is 43.

The spelling of 81500565715 in words is "eighty-one billion, five hundred million, five hundred sixty-five thousand, seven hundred fifteen".