198561911 has 4 divisors (see below), whose sum is σ = 198894000. Its totient is φ = 198229824.

The previous prime is 198561907. The next prime is 198561931. The reversal of 198561911 is 119165891.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 198561911 - 2² = 198561907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198561931) 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, 165146 + ... + 166343.

It is an arithmetic number, because the mean of its divisors is an integer number (49723500).

Almost surely, 2^198561911 is an apocalyptic number.

198561911 is a deficient number, since it is larger than the sum of its proper divisors (332089).

198561911 is an equidigital number, since it uses as much as digits as its factorization.

198561911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332088.

The product of its digits is 19440, while the sum is 41.

The square root of 198561911 is about 14091.1997714886. The cubic root of 198561911 is about 583.3985087087.

The spelling of 198561911 in words is "one hundred ninety-eight million, five hundred sixty-one thousand, nine hundred eleven".