198180181801817 has 2 divisors, whose sum is σ = 198180181801818. Its totient is φ = 198180181801816.

The previous prime is 198180181801783. The next prime is 198180181801883. The reversal of 198180181801817 is 718108181081891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197163272922256 + 1016908879561 = 14041484^2 + 1008419^2 .

It is a cyclic number.

It is not a de Polignac number, because 198180181801817 - 2³⁰ = 198179108059993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 198180181801817.

It is not a weakly prime, because it can be changed into another prime (198180181801117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99090090900908 + 99090090900909.

It is an arithmetic number, because the mean of its divisors is an integer number (99090090900909).

Almost surely, 2^{198180181801817} is an apocalyptic number.

It is an amenable number.

198180181801817 is a deficient number, since it is larger than the sum of its proper divisors (1).

198180181801817 is an equidigital number, since it uses as much as digits as its factorization.

198180181801817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2064384, while the sum is 62.

The spelling of 198180181801817 in words is "one hundred ninety-eight trillion, one hundred eighty billion, one hundred eighty-one million, eight hundred one thousand, eight hundred seventeen".