198811457561 has 2 divisors, whose sum is σ = 198811457562. Its totient is φ = 198811457560.

The previous prime is 198811457543. The next prime is 198811457627. The reversal of 198811457561 is 165754118891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197508247561 + 1303210000 = 444419^2 + 36100^2 .

It is a cyclic number.

It is not a de Polignac number, because 198811457561 - 2¹⁴ = 198811441177 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 198811457497 and 198811457506.

It is not a weakly prime, because it can be changed into another prime (198811457501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99405728780 + 99405728781.

It is an arithmetic number, because the mean of its divisors is an integer number (99405728781).

Almost surely, 2^198811457561 is an apocalyptic number.

It is an amenable number.

198811457561 is a deficient number, since it is larger than the sum of its proper divisors (1).

198811457561 is an equidigital number, since it uses as much as digits as its factorization.

198811457561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2419200, while the sum is 56.

The spelling of 198811457561 in words is "one hundred ninety-eight billion, eight hundred eleven million, four hundred fifty-seven thousand, five hundred sixty-one".