18565385379840 has 1568 divisors, whose sum is σ = 72620651486880. Its totient is φ = 4553792815104.

The previous prime is 18565385379809. The next prime is 18565385379857. The reversal of 18565385379840 is 4897358356581.

18565385379840 is a `hidden beast` number, since 1 + 8 + 5 + 6 + 5 + 3 + 8 + 537 + 9 + 84 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 65602068339 + ... + 65602068621.

Almost surely, 2^{18565385379840} is an apocalyptic number.

18565385379840 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 18565385379840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36310325743440).

18565385379840 is an abundant number, since it is smaller than the sum of its proper divisors (54055266107040).

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

18565385379840 is an frugal number, since it uses more digits than its factorization.

18565385379840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 870912000, while the sum is 72.

The spelling of 18565385379840 in words is "eighteen trillion, five hundred sixty-five billion, three hundred eighty-five million, three hundred seventy-nine thousand, eight hundred forty".