81687881239 has 16 divisors (see below), whose sum is σ = 84880332000. Its totient is φ = 78521264640.

The previous prime is 81687881213. The next prime is 81687881263. The reversal of 81687881239 is 93218878618.

It is a cyclic number.

It is not a de Polignac number, because 81687881239 - 2⁷ = 81687881111 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81687881039) 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, 6172972 + ... + 6186190.

It is an arithmetic number, because the mean of its divisors is an integer number (5305020750).

Almost surely, 2^81687881239 is an apocalyptic number.

81687881239 is a deficient number, since it is larger than the sum of its proper divisors (3192450761).

81687881239 is a wasteful number, since it uses less digits than its factorization.

81687881239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14178.

The product of its digits is 9289728, while the sum is 61.

The spelling of 81687881239 in words is "eighty-one billion, six hundred eighty-seven million, eight hundred eighty-one thousand, two hundred thirty-nine".