81681165118 has 16 divisors (see below), whose sum is σ = 140034338784. Its totient is φ = 35003842560.

The previous prime is 81681165113. The next prime is 81681165119. The reversal of 81681165118 is 81156118618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81681165113) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25146 + ... + 404962.

It is an arithmetic number, because the mean of its divisors is an integer number (8752146174).

Almost surely, 2^81681165118 is an apocalyptic number.

81681165118 is a deficient number, since it is larger than the sum of its proper divisors (58353173666).

81681165118 is a wasteful number, since it uses less digits than its factorization.

81681165118 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395187.

The product of its digits is 92160, while the sum is 46.

The spelling of 81681165118 in words is "eighty-one billion, six hundred eighty-one million, one hundred sixty-five thousand, one hundred eighteen".