819918819918 has 144 divisors (see below), whose sum is σ = 2005311134736. Its totient is φ = 239976000000.

The previous prime is 819918819911. The next prime is 819918819931.

819918819918 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819918819911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 82806768 + ... + 82816668.

It is an arithmetic number, because the mean of its divisors is an integer number (13925771769).

Almost surely, 2^819918819918 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 819918819918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1002655567368).

819918819918 is an abundant number, since it is smaller than the sum of its proper divisors (1185392314818).

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

819918819918 is a wasteful number, since it uses less digits than its factorization.

819918819918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10163 (or 10059 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 72.

The spelling of 819918819918 in words is "eight hundred nineteen billion, nine hundred eighteen million, eight hundred nineteen thousand, nine hundred eighteen".