199812161 has 2 divisors, whose sum is σ = 199812162. Its totient is φ = 199812160.

The previous prime is 199812139. The next prime is 199812187. The reversal of 199812161 is 161218991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198274561 + 1537600 = 14081^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 199812161 - 2⁶ = 199812097 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199812191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99906080 + 99906081.

It is an arithmetic number, because the mean of its divisors is an integer number (99906081).

Almost surely, 2^199812161 is an apocalyptic number.

It is an amenable number.

199812161 is a deficient number, since it is larger than the sum of its proper divisors (1).

199812161 is an equidigital number, since it uses as much as digits as its factorization.

199812161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 38.

The square root of 199812161 is about 14135.4929521400. The cubic root of 199812161 is about 584.6204087736.

The spelling of 199812161 in words is "one hundred ninety-nine million, eight hundred twelve thousand, one hundred sixty-one".