198191087 has 2 divisors, whose sum is σ = 198191088. Its totient is φ = 198191086.

The previous prime is 198191051. The next prime is 198191099. The reversal of 198191087 is 780191891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 198191087 - 2⁸ = 198190831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198191047) 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 as a sum of consecutive naturals, namely, 99095543 + 99095544.

It is an arithmetic number, because the mean of its divisors is an integer number (99095544).

Almost surely, 2^198191087 is an apocalyptic number.

198191087 is a deficient number, since it is larger than the sum of its proper divisors (1).

198191087 is an equidigital number, since it uses as much as digits as its factorization.

198191087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 44.

The square root of 198191087 is about 14078.0356229127. The cubic root of 198191087 is about 583.0351073873.

The spelling of 198191087 in words is "one hundred ninety-eight million, one hundred ninety-one thousand, eighty-seven".