18538813440 has 960 divisors, whose sum is σ = 79152353280. Its totient is φ = 4060938240.

The previous prime is 18538813373. The next prime is 18538813511. The reversal of 18538813440 is 4431883581.

18538813440 is a `hidden beast` number, since 1 + 8 + 538 + 81 + 34 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 179988429 + ... + 179988531.

It is an arithmetic number, because the mean of its divisors is an integer number (82450368).

Almost surely, 2^18538813440 is an apocalyptic number.

18538813440 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 18538813440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39576176640).

18538813440 is an abundant number, since it is smaller than the sum of its proper divisors (60613539840).

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

18538813440 is a wasteful number, since it uses less digits than its factorization.

18538813440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 18538813440 in words is "eighteen billion, five hundred thirty-eight million, eight hundred thirteen thousand, four hundred forty".