81909327718 has 32 divisors (see below), whose sum is σ = 130418684928. Its totient is φ = 38513944800.

The previous prime is 81909327697. The next prime is 81909327751. The reversal of 81909327718 is 81772390918.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1838421 + ... + 1882447.

It is an arithmetic number, because the mean of its divisors is an integer number (4075583904).

Almost surely, 2^81909327718 is an apocalyptic number.

81909327718 is a deficient number, since it is larger than the sum of its proper divisors (48509357210).

81909327718 is a wasteful number, since it uses less digits than its factorization.

81909327718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44908.

The product of its (nonzero) digits is 1524096, while the sum is 55.

The spelling of 81909327718 in words is "eighty-one billion, nine hundred nine million, three hundred twenty-seven thousand, seven hundred eighteen".