81113215205 has 16 divisors (see below), whose sum is σ = 106559803584. Its totient is φ = 58782967680.

The previous prime is 81113215187. The next prime is 81113215207. The reversal of 81113215205 is 50251231118.

It is not a de Polignac number, because 81113215205 - 2²² = 81109020901 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81113215207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2590064 + ... + 2621193.

It is an arithmetic number, because the mean of its divisors is an integer number (6659987724).

Almost surely, 2^81113215205 is an apocalyptic number.

It is an amenable number.

81113215205 is a deficient number, since it is larger than the sum of its proper divisors (25446588379).

81113215205 is a wasteful number, since it uses less digits than its factorization.

81113215205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5211556.

The product of its (nonzero) digits is 2400, while the sum is 29.

The spelling of 81113215205 in words is "eighty-one billion, one hundred thirteen million, two hundred fifteen thousand, two hundred five".