18391821020 has 48 divisors (see below), whose sum is σ = 41344732800. Its totient is φ = 6851396160.

The previous prime is 18391821017. The next prime is 18391821029. The reversal of 18391821020 is 2012819381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18391821029) by changing a digit.

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, 387746 + ... + 432585.

It is an arithmetic number, because the mean of its divisors is an integer number (861348600).

Almost surely, 2^18391821020 is an apocalyptic number.

18391821020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18391821020 is an abundant number, since it is smaller than the sum of its proper divisors (22952911780).

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

18391821020 is a wasteful number, since it uses less digits than its factorization.

18391821020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820418 (or 820416 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 35.

The spelling of 18391821020 in words is "eighteen billion, three hundred ninety-one million, eight hundred twenty-one thousand, twenty".