198923809 has 4 divisors (see below), whose sum is σ = 227341504. Its totient is φ = 170506116.

The previous prime is 198923773. The next prime is 198923819. The reversal of 198923809 is 908329891.

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 a cyclic number.

It is not a de Polignac number, because 198923809 - 2¹⁹ = 198399521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198923819) 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, 14208837 + ... + 14208850.

It is an arithmetic number, because the mean of its divisors is an integer number (56835376).

Almost surely, 2^198923809 is an apocalyptic number.

It is an amenable number.

198923809 is a deficient number, since it is larger than the sum of its proper divisors (28417695).

198923809 is an equidigital number, since it uses as much as digits as its factorization.

198923809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28417694.

The product of its (nonzero) digits is 279936, while the sum is 49.

The square root of 198923809 is about 14104.0352027354. The cubic root of 198923809 is about 583.7527267181.

The spelling of 198923809 in words is "one hundred ninety-eight million, nine hundred twenty-three thousand, eight hundred nine".