198809 has 8 divisors (see below), whose sum is σ = 219912. Its totient is φ = 178560.

The previous prime is 198769. The next prime is 198811. The reversal of 198809 is 908891.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 784 + 198025 = 28^2 + 445^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 198809 - 2⁸ = 198553 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 198809.

It is not an unprimeable number, because it can be changed into a prime (198829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 347 + ... + 719.

It is an arithmetic number, because the mean of its divisors is an integer number (27489).

2¹⁹⁸⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

198809 is a deficient number, since it is larger than the sum of its proper divisors (21103).

198809 is a wasteful number, since it uses less digits than its factorization.

198809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 198809 is about 445.8800287073. The cubic root of 198809 is about 58.3640400689.

Multiplying 198809 by its sum of digits (35), we get a triangular number (6958315 = T₃₇₃₀).

The spelling of 198809 in words is "one hundred ninety-eight thousand, eight hundred nine".