18423721944 has 128 divisors (see below), whose sum is σ = 54104544000. Its totient is φ = 5792746752.

The previous prime is 18423721909. The next prime is 18423721973. The reversal of 18423721944 is 44912732481.

18423721944 is a `hidden beast` number, since 1 + 8 + 423 + 7 + 219 + 4 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 18423721944.

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 31 ways as a sum of consecutive naturals, for example, 946599 + ... + 965865.

It is an arithmetic number, because the mean of its divisors is an integer number (422691750).

Almost surely, 2^18423721944 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18423721944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27052272000).

18423721944 is an abundant number, since it is smaller than the sum of its proper divisors (35680822056).

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

18423721944 is a wasteful number, since it uses less digits than its factorization.

18423721944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19534 (or 19524 counting only the distinct ones).

The product of its digits is 387072, while the sum is 45.

The spelling of 18423721944 in words is "eighteen billion, four hundred twenty-three million, seven hundred twenty-one thousand, nine hundred forty-four".