198309 has 4 divisors (see below), whose sum is σ = 264416. Its totient is φ = 132204.

The previous prime is 198301. The next prime is 198313. The reversal of 198309 is 903891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 198309 - 2³ = 198301 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

198309 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33049 + ... + 33054.

It is an arithmetic number, because the mean of its divisors is an integer number (66104).

2¹⁹⁸³⁰⁹ is an apocalyptic number.

It is an amenable number.

198309 is a deficient number, since it is larger than the sum of its proper divisors (66107).

198309 is an equidigital number, since it uses as much as digits as its factorization.

198309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66106.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 198309 is about 445.3189867949. The cubic root of 198309 is about 58.3150709272.

The spelling of 198309 in words is "one hundred ninety-eight thousand, three hundred nine".