18349321 has 2 divisors, whose sum is σ = 18349322. Its totient is φ = 18349320.

The previous prime is 18349319. The next prime is 18349327. The reversal of 18349321 is 12394381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10169721 + 8179600 = 3189^2 + 2860^2 .

It is a cyclic number.

It is not a de Polignac number, because 18349321 - 2¹ = 18349319 is a prime.

It is a super-2 number, since 2×18349321² = 673395162322082, which contains 22 as substring.

Together with 18349319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18349327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9174660 + 9174661.

It is an arithmetic number, because the mean of its divisors is an integer number (9174661).

Almost surely, 2^18349321 is an apocalyptic number.

It is an amenable number.

18349321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18349321 is an equidigital number, since it uses as much as digits as its factorization.

18349321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 31.

The square root of 18349321 is about 4283.6107432866. The cubic root of 18349321 is about 263.7586225403.

The spelling of 18349321 in words is "eighteen million, three hundred forty-nine thousand, three hundred twenty-one".