198805 has 4 divisors (see below), whose sum is σ = 238572. Its totient is φ = 159040.

The previous prime is 198769. The next prime is 198811. The reversal of 198805 is 508891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 508891 = 281 ⋅1811.

It can be written as a sum of positive squares in 2 ways, for example, as 40401 + 158404 = 201^2 + 398^2 .

It is not a de Polignac number, because 198805 - 2¹³ = 190613 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 19876 + ... + 19885.

It is an arithmetic number, because the mean of its divisors is an integer number (59643).

2¹⁹⁸⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

198805 is a deficient number, since it is larger than the sum of its proper divisors (39767).

198805 is an equidigital number, since it uses as much as digits as its factorization.

198805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39766.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 198805 is about 445.8755431732. The cubic root of 198805 is about 58.3636486418.

The spelling of 198805 in words is "one hundred ninety-eight thousand, eight hundred five".