81111159657 has 48 divisors (see below), whose sum is σ = 140388019200. Its totient is φ = 44546150880.

The previous prime is 81111159637. The next prime is 81111159659. The reversal of 81111159657 is 75695111118.

81111159657 is a `hidden beast` number, since 8 + 1 + 1 + 1 + 1 + 1 + 596 + 57 = 666.

It is not a de Polignac number, because 81111159657 - 2⁶ = 81111159593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81111159659) 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 47 ways as a sum of consecutive naturals, for example, 894157 + ... + 980682.

It is an arithmetic number, because the mean of its divisors is an integer number (2924750400).

Almost surely, 2^81111159657 is an apocalyptic number.

It is an amenable number.

81111159657 is a deficient number, since it is larger than the sum of its proper divisors (59276859543).

81111159657 is a wasteful number, since it uses less digits than its factorization.

81111159657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1874898 (or 1874895 counting only the distinct ones).

The product of its digits is 75600, while the sum is 45.

The spelling of 81111159657 in words is "eighty-one billion, one hundred eleven million, one hundred fifty-nine thousand, six hundred fifty-seven".