998819209 has 2 divisors, whose sum is σ = 998819210. Its totient is φ = 998819208.

The previous prime is 998819177. The next prime is 998819219. The reversal of 998819209 is 902918899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 768841984 + 229977225 = 27728^2 + 15165^2 .

It is an emirp because it is prime and its reverse (902918899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 998819209 - 2⁵ = 998819177 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 998819209.

It is not a weakly prime, because it can be changed into another prime (998819219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499409604 + 499409605.

It is an arithmetic number, because the mean of its divisors is an integer number (499409605).

Almost surely, 2^998819209 is an apocalyptic number.

It is an amenable number.

998819209 is a deficient number, since it is larger than the sum of its proper divisors (1).

998819209 is an equidigital number, since it uses as much as digits as its factorization.

998819209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 839808, while the sum is 55.

The square root of 998819209 is about 31604.1011420986. The cubic root of 998819209 is about 999.6062479797.

The spelling of 998819209 in words is "nine hundred ninety-eight million, eight hundred nineteen thousand, two hundred nine".