198851612261 has 2 divisors, whose sum is σ = 198851612262. Its totient is φ = 198851612260.

The previous prime is 198851612221. The next prime is 198851612269. The reversal of 198851612261 is 162216158891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192958132900 + 5893479361 = 439270^2 + 76769^2 .

It is an emirp because it is prime and its reverse (162216158891) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198851612261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198851612269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99425806130 + 99425806131.

It is an arithmetic number, because the mean of its divisors is an integer number (99425806131).

Almost surely, 2^198851612261 is an apocalyptic number.

It is an amenable number.

198851612261 is a deficient number, since it is larger than the sum of its proper divisors (1).

198851612261 is an equidigital number, since it uses as much as digits as its factorization.

198851612261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 414720, while the sum is 50.

The spelling of 198851612261 in words is "one hundred ninety-eight billion, eight hundred fifty-one million, six hundred twelve thousand, two hundred sixty-one".