81393887678 has 16 divisors (see below), whose sum is σ = 126397612080. Its totient is φ = 39263500416.

The previous prime is 81393887629. The next prime is 81393887681. The reversal of 81393887678 is 87678839318.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 461051 + ... + 612662.

It is an arithmetic number, because the mean of its divisors is an integer number (7899850755).

Almost surely, 2^81393887678 is an apocalyptic number.

81393887678 is a deficient number, since it is larger than the sum of its proper divisors (45003724402).

81393887678 is a wasteful number, since it uses less digits than its factorization.

81393887678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075051.

The product of its digits is 97542144, while the sum is 68.

The spelling of 81393887678 in words is "eighty-one billion, three hundred ninety-three million, eight hundred eighty-seven thousand, six hundred seventy-eight".