199919981161 has 2 divisors, whose sum is σ = 199919981162. Its totient is φ = 199919981160.

The previous prime is 199919981159. The next prime is 199919981257. The reversal of 199919981161 is 161189919991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 101549931561 + 98370049600 = 318669^2 + 313640^2 .

It is an emirp because it is prime and its reverse (161189919991) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 191186616661 and 166616681191.

It is a cyclic number.

It is not a de Polignac number, because 199919981161 - 2¹ = 199919981159 is a prime.

Together with 199919981159, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 199919981093 and 199919981102.

It is not a weakly prime, because it can be changed into another prime (199919931161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99959990580 + 99959990581.

It is an arithmetic number, because the mean of its divisors is an integer number (99959990581).

Almost surely, 2^199919981161 is an apocalyptic number.

It is an amenable number.

199919981161 is a deficient number, since it is larger than the sum of its proper divisors (1).

199919981161 is an equidigital number, since it uses as much as digits as its factorization.

199919981161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2834352, while the sum is 64.

The spelling of 199919981161 in words is "one hundred ninety-nine billion, nine hundred nineteen million, nine hundred eighty-one thousand, one hundred sixty-one".