18205321 has 2 divisors, whose sum is σ = 18205322. Its totient is φ = 18205320.

The previous prime is 18205273. The next prime is 18205333. The reversal of 18205321 is 12350281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15515721 + 2689600 = 3939^2 + 1640^2 .

It is an emirp because it is prime and its reverse (12350281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18205321 - 2¹³ = 18197129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18205292 and 18205301.

It is not a weakly prime, because it can be changed into another prime (18205391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9102660 + 9102661.

It is an arithmetic number, because the mean of its divisors is an integer number (9102661).

Almost surely, 2^18205321 is an apocalyptic number.

It is an amenable number.

18205321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18205321 is an equidigital number, since it uses as much as digits as its factorization.

18205321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 18205321 is about 4266.7693867843. The cubic root of 18205321 is about 263.0668434049.

The spelling of 18205321 in words is "eighteen million, two hundred five thousand, three hundred twenty-one".