199681619 has 2 divisors, whose sum is σ = 199681620. Its totient is φ = 199681618.

The previous prime is 199681589. The next prime is 199681663. The reversal of 199681619 is 916186991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199681619 - 2¹² = 199677523 is a prime.

It is a super-4 number, since 4×199681619⁴ (a number of 34 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199681679) 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, 99840809 + 99840810.

It is an arithmetic number, because the mean of its divisors is an integer number (99840810).

Almost surely, 2^199681619 is an apocalyptic number.

199681619 is a deficient number, since it is larger than the sum of its proper divisors (1).

199681619 is an equidigital number, since it uses as much as digits as its factorization.

199681619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 50.

The square root of 199681619 is about 14130.8746721496. The cubic root of 199681619 is about 584.4930656011.

The spelling of 199681619 in words is "one hundred ninety-nine million, six hundred eighty-one thousand, six hundred nineteen".