199989919 has 2 divisors, whose sum is σ = 199989920. Its totient is φ = 199989918.

The previous prime is 199989917. The next prime is 199989929. The reversal of 199989919 is 919989991.

It is a weak prime.

It is an emirp because it is prime and its reverse (919989991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199989919 - 2¹ = 199989917 is a prime.

It is a super-2 number, since 2×199989919² = 79991935403253122, which contains 22 as substring.

Together with 199989917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199989917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99994959 + 99994960.

It is an arithmetic number, because the mean of its divisors is an integer number (99994960).

Almost surely, 2^199989919 is an apocalyptic number.

199989919 is a deficient number, since it is larger than the sum of its proper divisors (1).

199989919 is an equidigital number, since it uses as much as digits as its factorization.

199989919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4251528, while the sum is 64.

The square root of 199989919 is about 14141.7792020665. The cubic root of 199989919 is about 584.7937218032.

The spelling of 199989919 in words is "one hundred ninety-nine million, nine hundred eighty-nine thousand, nine hundred nineteen".