81244993818 has 16 divisors (see below), whose sum is σ = 162760360896. Its totient is φ = 27036602400.

The previous prime is 81244993807. The next prime is 81244993853. The reversal of 81244993818 is 81839944218.

It is a Curzon 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 7 ways as a sum of consecutive naturals, for example, 11261646 + ... + 11268857.

It is an arithmetic number, because the mean of its divisors is an integer number (10172522556).

Almost surely, 2^81244993818 is an apocalyptic number.

81244993818 is an abundant number, since it is smaller than the sum of its proper divisors (81515367078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81244993818 is a wasteful number, since it uses less digits than its factorization.

81244993818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22531109.

The product of its digits is 3981312, while the sum is 57.

The spelling of 81244993818 in words is "eighty-one billion, two hundred forty-four million, nine hundred ninety-three thousand, eight hundred eighteen".