198717817 has 2 divisors, whose sum is σ = 198717818. Its totient is φ = 198717816.

The previous prime is 198717763. The next prime is 198717821. The reversal of 198717817 is 718717891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 171636201 + 27081616 = 13101^2 + 5204^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198717817 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (198717847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99358908 + 99358909.

It is an arithmetic number, because the mean of its divisors is an integer number (99358909).

Almost surely, 2^198717817 is an apocalyptic number.

It is an amenable number.

198717817 is a deficient number, since it is larger than the sum of its proper divisors (1).

198717817 is an equidigital number, since it uses as much as digits as its factorization.

198717817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 197568, while the sum is 49.

The square root of 198717817 is about 14096.7307202770. The cubic root of 198717817 is about 583.5511588863.

The spelling of 198717817 in words is "one hundred ninety-eight million, seven hundred seventeen thousand, eight hundred seventeen".