198872809 has 2 divisors, whose sum is σ = 198872810. Its totient is φ = 198872808.

The previous prime is 198872777. The next prime is 198872831. The reversal of 198872809 is 908278891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196784784 + 2088025 = 14028^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 198872809 - 2⁵ = 198872777 is a prime.

It is not a weakly prime, because it can be changed into another prime (198872209) 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, 99436404 + 99436405.

It is an arithmetic number, because the mean of its divisors is an integer number (99436405).

Almost surely, 2^198872809 is an apocalyptic number.

It is an amenable number.

198872809 is a deficient number, since it is larger than the sum of its proper divisors (1).

198872809 is an equidigital number, since it uses as much as digits as its factorization.

198872809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 580608, while the sum is 52.

The square root of 198872809 is about 14102.2270936189. The cubic root of 198872809 is about 583.7028350304.

The spelling of 198872809 in words is "one hundred ninety-eight million, eight hundred seventy-two thousand, eight hundred nine".