198555563621951 has 2 divisors, whose sum is σ = 198555563621952. Its totient is φ = 198555563621950.

The previous prime is 198555563621941. The next prime is 198555563621963. The reversal of 198555563621951 is 159126365555891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 198555563621951 - 2³⁰ = 198554489880127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198555563621941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99277781810975 + 99277781810976.

It is an arithmetic number, because the mean of its divisors is an integer number (99277781810976).

Almost surely, 2^{198555563621951} is an apocalyptic number.

198555563621951 is a deficient number, since it is larger than the sum of its proper divisors (1).

198555563621951 is an equidigital number, since it uses as much as digits as its factorization.

198555563621951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 437400000, while the sum is 71.

The spelling of 198555563621951 in words is "one hundred ninety-eight trillion, five hundred fifty-five billion, five hundred sixty-three million, six hundred twenty-one thousand, nine hundred fifty-one".