198851612221 has 2 divisors, whose sum is σ = 198851612222. Its totient is φ = 198851612220.

The previous prime is 198851612159. The next prime is 198851612261. The reversal of 198851612221 is 122216158891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109901532196 + 88950080025 = 331514^2 + 298245^2 .

It is an emirp because it is prime and its reverse (122216158891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198851612221 - 2⁷ = 198851612093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198851612261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99425806110 + 99425806111.

It is an arithmetic number, because the mean of its divisors is an integer number (99425806111).

Almost surely, 2^198851612221 is an apocalyptic number.

It is an amenable number.

198851612221 is a deficient number, since it is larger than the sum of its proper divisors (1).

198851612221 is an equidigital number, since it uses as much as digits as its factorization.

198851612221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 46.

The spelling of 198851612221 in words is "one hundred ninety-eight billion, eight hundred fifty-one million, six hundred twelve thousand, two hundred twenty-one".