18345989 has 2 divisors, whose sum is σ = 18345990. Its totient is φ = 18345988.

The previous prime is 18345967. The next prime is 18346021. The reversal of 18345989 is 98954381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14212900 + 4133089 = 3770^2 + 2033^2 .

It is a cyclic number.

It is not a de Polignac number, because 18345989 - 2¹² = 18341893 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18345949) 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, 9172994 + 9172995.

It is an arithmetic number, because the mean of its divisors is an integer number (9172995).

Almost surely, 2^18345989 is an apocalyptic number.

It is an amenable number.

18345989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18345989 is an equidigital number, since it uses as much as digits as its factorization.

18345989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 47.

The square root of 18345989 is about 4283.2218014014. The cubic root of 18345989 is about 263.7426565193.

The spelling of 18345989 in words is "eighteen million, three hundred forty-five thousand, nine hundred eighty-nine".