199917691 has 2 divisors, whose sum is σ = 199917692. Its totient is φ = 199917690.

The previous prime is 199917689. The next prime is 199917713. The reversal of 199917691 is 196719991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199917691 - 2¹ = 199917689 is a prime.

Together with 199917689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (199917391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99958845 + 99958846.

It is an arithmetic number, because the mean of its divisors is an integer number (99958846).

Almost surely, 2^199917691 is an apocalyptic number.

199917691 is a deficient number, since it is larger than the sum of its proper divisors (1).

199917691 is an equidigital number, since it uses as much as digits as its factorization.

199917691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 275562, while the sum is 52.

The square root of 199917691 is about 14139.2252616613. The cubic root of 199917691 is about 584.7233123094.

The spelling of 199917691 in words is "one hundred ninety-nine million, nine hundred seventeen thousand, six hundred ninety-one".