18381219840 has 576 divisors, whose sum is σ = 67612708800. Its totient is φ = 4788191232.

The previous prime is 18381219839. The next prime is 18381219869. The reversal of 18381219840 is 4891218381.

18381219840 is a `hidden beast` number, since 18 + 381 + 219 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 206530516 + ... + 206530604.

It is an arithmetic number, because the mean of its divisors is an integer number (117383175).

Almost surely, 2^18381219840 is an apocalyptic number.

18381219840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18381219840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33806354400).

18381219840 is an abundant number, since it is smaller than the sum of its proper divisors (49231488960).

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

18381219840 is an frugal number, since it uses more digits than its factorization.

18381219840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214 (or 182 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 45.

The spelling of 18381219840 in words is "eighteen billion, three hundred eighty-one million, two hundred nineteen thousand, eight hundred forty".