1998358209 has 15 divisors (see below), whose sum is σ = 2985802897. Its totient is φ = 1331970588.

The previous prime is 1998358171. The next prime is 1998358217. The reversal of 1998358209 is 9028538991.

The square root of 1998358209 is 44703.

It is a perfect power (a square), and thus also a powerful number.

It is a de Polignac number, because none of the positive numbers 2^k-1998358209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1998358249) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 399844 + ... + 404810.

Almost surely, 2^1998358209 is an apocalyptic number.

1998358209 is the 44703-rd square number.

1998358209 is the 22352-nd centered octagonal number.

It is an amenable number.

1998358209 is a deficient number, since it is larger than the sum of its proper divisors (987444688).

1998358209 is an frugal number, since it uses more digits than its factorization.

1998358209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9946 (or 4970 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 54.

The cubic root of 1998358209 is about 1259.5762010093.

The spelling of 1998358209 in words is "one billion, nine hundred ninety-eight million, three hundred fifty-eight thousand, two hundred nine".