81687278823 has 16 divisors (see below), whose sum is σ = 111942266880. Its totient is φ = 52959999456.

The previous prime is 81687278819. The next prime is 81687278857. The reversal of 81687278823 is 32887278618.

It is not a de Polignac number, because 81687278823 - 2² = 81687278819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81687278863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1822903 + ... + 1867176.

It is an arithmetic number, because the mean of its divisors is an integer number (6996391680).

Almost surely, 2^81687278823 is an apocalyptic number.

81687278823 is a deficient number, since it is larger than the sum of its proper divisors (30254988057).

81687278823 is a wasteful number, since it uses less digits than its factorization.

81687278823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3690286.

The product of its digits is 14450688, while the sum is 60.

The spelling of 81687278823 in words is "eighty-one billion, six hundred eighty-seven million, two hundred seventy-eight thousand, eight hundred twenty-three".