998909 has 2 divisors, whose sum is σ = 998910. Its totient is φ = 998908.

The previous prime is 998897. The next prime is 998917. The reversal of 998909 is 909899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 994009 + 4900 = 997^2 + 70^2 .

It is an emirp because it is prime and its reverse (909899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 998909 - 2⁸ = 998653 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 998909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499454 + 499455.

It is an arithmetic number, because the mean of its divisors is an integer number (499455).

2⁹⁹⁸⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

998909 is a deficient number, since it is larger than the sum of its proper divisors (1).

998909 is an equidigital number, since it uses as much as digits as its factorization.

998909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 44.

The square root of 998909 is about 999.4543511337. The cubic root of 998909 is about 99.9636201000.

It can be divided in two parts, 99890 and 9, that added together give a palindrome (99899).

The spelling of 998909 in words is "nine hundred ninety-eight thousand, nine hundred nine".