18809321 has 2 divisors, whose sum is σ = 18809322. Its totient is φ = 18809320.

The previous prime is 18809309. The next prime is 18809369. The reversal of 18809321 is 12390881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18619225 + 190096 = 4315^2 + 436^2 .

It is a cyclic number.

It is not a de Polignac number, because 18809321 - 2⁶ = 18809257 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18809521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9404660 + 9404661.

It is an arithmetic number, because the mean of its divisors is an integer number (9404661).

Almost surely, 2^18809321 is an apocalyptic number.

It is an amenable number.

18809321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18809321 is an equidigital number, since it uses as much as digits as its factorization.

18809321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 18809321 is about 4336.9714087137. The cubic root of 18809321 is about 265.9445161002.

The spelling of 18809321 in words is "eighteen million, eight hundred nine thousand, three hundred twenty-one".