18338505503521 has 32 divisors (see below), whose sum is σ = 21226780143360. Its totient is φ = 15518283264000.

The previous prime is 18338505503519. The next prime is 18338505503533. The reversal of 18338505503521 is 12530550583381.

It is a cyclic number.

It is not a de Polignac number, because 18338505503521 - 2¹ = 18338505503519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18338505503821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 731859025 + ... + 731884081.

It is an arithmetic number, because the mean of its divisors is an integer number (663336879480).

Almost surely, 2^{18338505503521} is an apocalyptic number.

It is an amenable number.

18338505503521 is a deficient number, since it is larger than the sum of its proper divisors (2888274639839).

18338505503521 is a wasteful number, since it uses less digits than its factorization.

18338505503521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28105.

The product of its (nonzero) digits is 2160000, while the sum is 49.

The spelling of 18338505503521 in words is "eighteen trillion, three hundred thirty-eight billion, five hundred five million, five hundred three thousand, five hundred twenty-one".