18784135353521 has 16 divisors (see below), whose sum is σ = 18981543430080. Its totient is φ = 18587695660800.

The previous prime is 18784135353421. The next prime is 18784135353539. The reversal of 18784135353521 is 12535353148781.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18784135353521 - 2²⁶ = 18784068244657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18784135353541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54086990 + ... + 54433176.

It is an arithmetic number, because the mean of its divisors is an integer number (1186346464380).

Almost surely, 2^{18784135353521} is an apocalyptic number.

It is an amenable number.

18784135353521 is a deficient number, since it is larger than the sum of its proper divisors (197408076559).

18784135353521 is a wasteful number, since it uses less digits than its factorization.

18784135353521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347584.

The product of its digits is 12096000, while the sum is 56.

The spelling of 18784135353521 in words is "eighteen trillion, seven hundred eighty-four billion, one hundred thirty-five million, three hundred fifty-three thousand, five hundred twenty-one".