198905689 has 4 divisors (see below), whose sum is σ = 202166500. Its totient is φ = 195644880.

The previous prime is 198905621. The next prime is 198905711. The reversal of 198905689 is 986509891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986509891 = 17491 ⋅56401.

It can be written as a sum of positive squares in 2 ways, for example, as 22467600 + 176438089 = 4740^2 + 13283^2 .

It is a cyclic number.

It is not a de Polignac number, because 198905689 - 2⁹ = 198905177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198905789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1630314 + ... + 1630435.

It is an arithmetic number, because the mean of its divisors is an integer number (50541625).

Almost surely, 2^198905689 is an apocalyptic number.

It is an amenable number.

198905689 is a deficient number, since it is larger than the sum of its proper divisors (3260811).

198905689 is an equidigital number, since it uses as much as digits as its factorization.

198905689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3260810.

The product of its (nonzero) digits is 1399680, while the sum is 55.

The square root of 198905689 is about 14103.3928187511. The cubic root of 198905689 is about 583.7350014717.

The spelling of 198905689 in words is "one hundred ninety-eight million, nine hundred five thousand, six hundred eighty-nine".