81115691727 has 96 divisors (see below), whose sum is σ = 135120912384. Its totient is φ = 42350817600.

The previous prime is 81115691719. The next prime is 81115691729. The reversal of 81115691727 is 72719651118.

It is not a de Polignac number, because 81115691727 - 2³ = 81115691719 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81115691729) 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 95 ways as a sum of consecutive naturals, for example, 128550702 + ... + 128551332.

It is an arithmetic number, because the mean of its divisors is an integer number (1407509504).

Almost surely, 2^81115691727 is an apocalyptic number.

81115691727 is a deficient number, since it is larger than the sum of its proper divisors (54005220657).

81115691727 is a wasteful number, since it uses less digits than its factorization.

81115691727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1257 (or 1238 counting only the distinct ones).

The product of its digits is 211680, while the sum is 48.

The spelling of 81115691727 in words is "eighty-one billion, one hundred fifteen million, six hundred ninety-one thousand, seven hundred twenty-seven".