198771961 has 2 divisors, whose sum is σ = 198771962. Its totient is φ = 198771960.

The previous prime is 198771953. The next prime is 198772009. The reversal of 198771961 is 169177891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154629225 + 44142736 = 12435^2 + 6644^2 .

It is an emirp because it is prime and its reverse (169177891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198771961 - 2³ = 198771953 is a prime.

It is not a weakly prime, because it can be changed into another prime (198771761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99385980 + 99385981.

It is an arithmetic number, because the mean of its divisors is an integer number (99385981).

Almost surely, 2^198771961 is an apocalyptic number.

It is an amenable number.

198771961 is a deficient number, since it is larger than the sum of its proper divisors (1).

198771961 is an equidigital number, since it uses as much as digits as its factorization.

198771961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 49.

The square root of 198771961 is about 14098.6510347622. The cubic root of 198771961 is about 583.6041535050.

The spelling of 198771961 in words is "one hundred ninety-eight million, seven hundred seventy-one thousand, nine hundred sixty-one".