999998309 has 2 divisors, whose sum is σ = 999998310. Its totient is φ = 999998308.

The previous prime is 999998269. The next prime is 999998339. The reversal of 999998309 is 903899999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 706390084 + 293608225 = 26578^2 + 17135^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999998309 is a prime.

It is a Sophie Germain 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 (999998339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999154 + 499999155.

It is an arithmetic number, because the mean of its divisors is an integer number (499999155).

Almost surely, 2^999998309 is an apocalyptic number.

It is an amenable number.

999998309 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998309 is an equidigital number, since it uses as much as digits as its factorization.

999998309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12754584, while the sum is 65.

The square root of 999998309 is about 31622.7498646149. The cubic root of 999998309 is about 999.9994363330. Note that the first 3 decimals are identical.

The spelling of 999998309 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, three hundred nine".