198940109 has 2 divisors, whose sum is σ = 198940110. Its totient is φ = 198940108.

The previous prime is 198940099. The next prime is 198940117. The reversal of 198940109 is 901049891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196084009 + 2856100 = 14003^2 + 1690^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198940109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198940909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99470054 + 99470055.

It is an arithmetic number, because the mean of its divisors is an integer number (99470055).

Almost surely, 2^198940109 is an apocalyptic number.

It is an amenable number.

198940109 is a deficient number, since it is larger than the sum of its proper divisors (1).

198940109 is an equidigital number, since it uses as much as digits as its factorization.

198940109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 198940109 is about 14104.6130397115. The cubic root of 198940109 is about 583.7686706945.

The spelling of 198940109 in words is "one hundred ninety-eight million, nine hundred forty thousand, one hundred nine".