18398609 has 2 divisors, whose sum is σ = 18398610. Its totient is φ = 18398608.

The previous prime is 18398599. The next prime is 18398647. The reversal of 18398609 is 90689381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9784384 + 8614225 = 3128^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 18398609 - 2⁸ = 18398353 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18398609.

It is not a weakly prime, because it can be changed into another prime (18398659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9199304 + 9199305.

It is an arithmetic number, because the mean of its divisors is an integer number (9199305).

Almost surely, 2^18398609 is an apocalyptic number.

It is an amenable number.

18398609 is a deficient number, since it is larger than the sum of its proper divisors (1).

18398609 is an equidigital number, since it uses as much as digits as its factorization.

18398609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 18398609 is about 4289.3599755675. The cubic root of 18398609 is about 263.9945715520.

The spelling of 18398609 in words is "eighteen million, three hundred ninety-eight thousand, six hundred nine".