198511109 has 2 divisors, whose sum is σ = 198511110. Its totient is φ = 198511108.

The previous prime is 198511067. The next prime is 198511111. The reversal of 198511109 is 901115891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163072900 + 35438209 = 12770^2 + 5953^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198511109 is a prime.

Together with 198511111, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198511139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99255554 + 99255555.

It is an arithmetic number, because the mean of its divisors is an integer number (99255555).

Almost surely, 2^198511109 is an apocalyptic number.

It is an amenable number.

198511109 is a deficient number, since it is larger than the sum of its proper divisors (1).

198511109 is an equidigital number, since it uses as much as digits as its factorization.

198511109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 35.

The square root of 198511109 is about 14089.3970417474. The cubic root of 198511109 is about 583.3487503590.

The spelling of 198511109 in words is "one hundred ninety-eight million, five hundred eleven thousand, one hundred nine".