18317321 has 4 divisors (see below), whose sum is σ = 19982544. Its totient is φ = 16652100.

The previous prime is 18317309. The next prime is 18317323. The reversal of 18317321 is 12371381.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18317321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18317323) 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, 832595 + ... + 832616.

It is an arithmetic number, because the mean of its divisors is an integer number (4995636).

Almost surely, 2^18317321 is an apocalyptic number.

18317321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18317321 is a deficient number, since it is larger than the sum of its proper divisors (1665223).

18317321 is a wasteful number, since it uses less digits than its factorization.

18317321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1665222.

The product of its digits is 1008, while the sum is 26.

The square root of 18317321 is about 4279.8739467419. The cubic root of 18317321 is about 263.6052074701.

The spelling of 18317321 in words is "eighteen million, three hundred seventeen thousand, three hundred twenty-one".