81149891105 has 16 divisors (see below), whose sum is σ = 101673480960. Its totient is φ = 62060822208.

The previous prime is 81149891083. The next prime is 81149891107. The reversal of 81149891105 is 50119894118.

It is a cyclic number.

It is not a de Polignac number, because 81149891105 - 2²⁸ = 80881455649 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81149891105.

It is not an unprimeable number, because it can be changed into a prime (81149891107) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9917 + ... + 402986.

It is an arithmetic number, because the mean of its divisors is an integer number (6354592560).

Almost surely, 2^81149891105 is an apocalyptic number.

It is an amenable number.

81149891105 is a deficient number, since it is larger than the sum of its proper divisors (20523589855).

81149891105 is a wasteful number, since it uses less digits than its factorization.

81149891105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414640.

The product of its (nonzero) digits is 103680, while the sum is 47.

The spelling of 81149891105 in words is "eighty-one billion, one hundred forty-nine million, eight hundred ninety-one thousand, one hundred five".