998817718909 has 2 divisors, whose sum is σ = 998817718910. Its totient is φ = 998817718908.

The previous prime is 998817718867. The next prime is 998817718937. The reversal of 998817718909 is 909817718899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 932485716409 + 66332002500 = 965653^2 + 257550^2 .

It is a cyclic number.

It is not a de Polignac number, because 998817718909 - 2¹³ = 998817710717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998817718949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499408859454 + 499408859455.

It is an arithmetic number, because the mean of its divisors is an integer number (499408859455).

Almost surely, 2^998817718909 is an apocalyptic number.

It is an amenable number.

998817718909 is a deficient number, since it is larger than the sum of its proper divisors (1).

998817718909 is an equidigital number, since it uses as much as digits as its factorization.

998817718909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164602368, while the sum is 76.

The spelling of 998817718909 in words is "nine hundred ninety-eight billion, eight hundred seventeen million, seven hundred eighteen thousand, nine hundred nine".