81593865987 has 8 divisors (see below), whose sum is σ = 108796512000. Its totient is φ = 54393565320.

The previous prime is 81593865971. The next prime is 81593866007. The reversal of 81593865987 is 78956839518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81593865987 - 2⁴ = 81593865971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81593865917) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 503487 + ... + 645512.

It is an arithmetic number, because the mean of its divisors is an integer number (13599564000).

Almost surely, 2^81593865987 is an apocalyptic number.

81593865987 is a deficient number, since it is larger than the sum of its proper divisors (27202646013).

81593865987 is a wasteful number, since it uses less digits than its factorization.

81593865987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172673.

The product of its digits is 130636800, while the sum is 69.

The spelling of 81593865987 in words is "eighty-one billion, five hundred ninety-three million, eight hundred sixty-five thousand, nine hundred eighty-seven".