18305993 has 2 divisors, whose sum is σ = 18305994. Its totient is φ = 18305992.

The previous prime is 18305971. The next prime is 18306011. The reversal of 18305993 is 39950381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14417209 + 3888784 = 3797^2 + 1972^2 .

It is a cyclic number.

It is not a de Polignac number, because 18305993 - 2⁶ = 18305929 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18355993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9152996 + 9152997.

It is an arithmetic number, because the mean of its divisors is an integer number (9152997).

Almost surely, 2^18305993 is an apocalyptic number.

It is an amenable number.

18305993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18305993 is an equidigital number, since it uses as much as digits as its factorization.

18305993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 18305993 is about 4278.5503386077. The cubic root of 18305993 is about 263.5508557162.

The spelling of 18305993 in words is "eighteen million, three hundred five thousand, nine hundred ninety-three".