18218217318321 has 4 divisors (see below), whose sum is σ = 24290956424432. Its totient is φ = 12145478212212.

The previous prime is 18218217318319. The next prime is 18218217318397. The reversal of 18218217318321 is 12381371281281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18218217318321 - 2¹ = 18218217318319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18218217318421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3036369553051 + ... + 3036369553056.

It is an arithmetic number, because the mean of its divisors is an integer number (6072739106108).

Almost surely, 2^{18218217318321} is an apocalyptic number.

It is an amenable number.

18218217318321 is a deficient number, since it is larger than the sum of its proper divisors (6072739106111).

18218217318321 is an equidigital number, since it uses as much as digits as its factorization.

18218217318321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6072739106110.

The product of its digits is 258048, while the sum is 48.

The spelling of 18218217318321 in words is "eighteen trillion, two hundred eighteen billion, two hundred seventeen million, three hundred eighteen thousand, three hundred twenty-one".