198790121 has 6 divisors (see below), whose sum is σ = 202614510. Its totient is φ = 195036608.

The previous prime is 198790117. The next prime is 198790183. The reversal of 198790121 is 121097891.

It can be written as a sum of positive squares in 3 ways, for example, as 114811225 + 83978896 = 10715^2 + 9164^2 .

It is not a de Polignac number, because 198790121 - 2² = 198790117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (198790421) 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 5 ways as a sum of consecutive naturals, for example, 32576 + ... + 38193.

It is an arithmetic number, because the mean of its divisors is an integer number (33769085).

Almost surely, 2^198790121 is an apocalyptic number.

It is an amenable number.

198790121 is a deficient number, since it is larger than the sum of its proper divisors (3824389).

198790121 is an frugal number, since it uses more digits than its factorization.

198790121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70875 (or 70822 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 38.

The square root of 198790121 is about 14099.2950532997. The cubic root of 198790121 is about 583.6219258451.

The spelling of 198790121 in words is "one hundred ninety-eight million, seven hundred ninety thousand, one hundred twenty-one".