18398309 has 2 divisors, whose sum is σ = 18398310. Its totient is φ = 18398308.

The previous prime is 18398279. The next prime is 18398333. The reversal of 18398309 is 90389381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16785409 + 1612900 = 4097^2 + 1270^2 .

It is a cyclic number.

It is not a de Polignac number, because 18398309 - 2¹² = 18394213 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18398339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9199154 + 9199155.

It is an arithmetic number, because the mean of its divisors is an integer number (9199155).

Almost surely, 2^18398309 is an apocalyptic number.

It is an amenable number.

18398309 is a deficient number, since it is larger than the sum of its proper divisors (1).

18398309 is an equidigital number, since it uses as much as digits as its factorization.

18398309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 18398309 is about 4289.3250051727. The cubic root of 18398309 is about 263.9931366826.

The spelling of 18398309 in words is "eighteen million, three hundred ninety-eight thousand, three hundred nine".