198438908081 has 2 divisors, whose sum is σ = 198438908082. Its totient is φ = 198438908080.

The previous prime is 198438908029. The next prime is 198438908089. The reversal of 198438908081 is 180809834891.

198438908081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198188793856 + 250114225 = 445184^2 + 15815^2 .

It is a cyclic number.

It is not a de Polignac number, because 198438908081 - 2³⁴ = 181259038897 is a prime.

It is a super-2 number, since 2×198438908081² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 198438908081.

It is not a weakly prime, because it can be changed into another prime (198438908089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99219454040 + 99219454041.

It is an arithmetic number, because the mean of its divisors is an integer number (99219454041).

Almost surely, 2^198438908081 is an apocalyptic number.

It is an amenable number.

198438908081 is a deficient number, since it is larger than the sum of its proper divisors (1).

198438908081 is an equidigital number, since it uses as much as digits as its factorization.

198438908081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3981312, while the sum is 59.

The spelling of 198438908081 in words is "one hundred ninety-eight billion, four hundred thirty-eight million, nine hundred eight thousand, eighty-one".