198665121 has 8 divisors (see below), whose sum is σ = 278828320. Its totient is φ = 125472672.

The previous prime is 198665107. The next prime is 198665123. The reversal of 198665121 is 121566891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 198665121 - 2¹⁰ = 198664097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 198665121.

It is not an unprimeable number, because it can be changed into a prime (198665123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1742620 + ... + 1742733.

It is an arithmetic number, because the mean of its divisors is an integer number (34853540).

Almost surely, 2^198665121 is an apocalyptic number.

It is an amenable number.

198665121 is a deficient number, since it is larger than the sum of its proper divisors (80163199).

198665121 is a wasteful number, since it uses less digits than its factorization.

198665121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3485375.

The product of its digits is 25920, while the sum is 39.

The square root of 198665121 is about 14094.8615104938. The cubic root of 198665121 is about 583.4995722849.

The spelling of 198665121 in words is "one hundred ninety-eight million, six hundred sixty-five thousand, one hundred twenty-one".