198451108805549 has 2 divisors, whose sum is σ = 198451108805550. Its totient is φ = 198451108805548.

The previous prime is 198451108805519. The next prime is 198451108805563. The reversal of 198451108805549 is 945508801154891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 136567036716100 + 61884072089449 = 11686190^2 + 7866643^2 .

It is an emirp because it is prime and its reverse (945508801154891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198451108805549 - 2²⁴ = 198451092028333 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198451108805519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99225554402774 + 99225554402775.

It is an arithmetic number, because the mean of its divisors is an integer number (99225554402775).

Almost surely, 2^{198451108805549} is an apocalyptic number.

It is an amenable number.

198451108805549 is a deficient number, since it is larger than the sum of its proper divisors (1).

198451108805549 is an equidigital number, since it uses as much as digits as its factorization.

198451108805549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944000, while the sum is 68.

The spelling of 198451108805549 in words is "one hundred ninety-eight trillion, four hundred fifty-one billion, one hundred eight million, eight hundred five thousand, five hundred forty-nine".