18317071321 has 4 divisors (see below), whose sum is σ = 18948694500. Its totient is φ = 17685448144.

The previous prime is 18317071313. The next prime is 18317071351. The reversal of 18317071321 is 12317071381.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11496128400 + 6820942921 = 107220^2 + 82589^2 .

It is a cyclic number.

It is not a de Polignac number, because 18317071321 - 2³ = 18317071313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18317071351) 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, 315811546 + ... + 315811603.

It is an arithmetic number, because the mean of its divisors is an integer number (4737173625).

Almost surely, 2^18317071321 is an apocalyptic number.

It is an amenable number.

18317071321 is a deficient number, since it is larger than the sum of its proper divisors (631623179).

18317071321 is an equidigital number, since it uses as much as digits as its factorization.

18317071321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 631623178.

The product of its (nonzero) digits is 7056, while the sum is 34.

The spelling of 18317071321 in words is "eighteen billion, three hundred seventeen million, seventy-one thousand, three hundred twenty-one".