199611221 has 2 divisors, whose sum is σ = 199611222. Its totient is φ = 199611220.

The previous prime is 199611199. The next prime is 199611233. The reversal of 199611221 is 122116991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 102292996 + 97318225 = 10114^2 + 9865^2 .

It is an emirp because it is prime and its reverse (122116991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199611221 - 2¹⁰ = 199610197 is a prime.

It is a super-2 number, since 2×199611221² = 79689279098221682, which contains 22 as substring.

It is equal to p_11058647 and since 199611221 and 11058647 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199611281) 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, 99805610 + 99805611.

It is an arithmetic number, because the mean of its divisors is an integer number (99805611).

Almost surely, 2^199611221 is an apocalyptic number.

It is an amenable number.

199611221 is a deficient number, since it is larger than the sum of its proper divisors (1).

199611221 is an equidigital number, since it uses as much as digits as its factorization.

199611221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 32.

The square root of 199611221 is about 14128.3835239563. The cubic root of 199611221 is about 584.4243696115.

The spelling of 199611221 in words is "one hundred ninety-nine million, six hundred eleven thousand, two hundred twenty-one".