199899391 has 4 divisors (see below), whose sum is σ = 202883032. Its totient is φ = 196915752.

The previous prime is 199899383. The next prime is 199899421. The reversal of 199899391 is 193998991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193998991 = 617 ⋅314423.

It is a cyclic number.

It is not a de Polignac number, because 199899391 - 2³ = 199899383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199899341) 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 in 3 ways as a sum of consecutive naturals, for example, 1491720 + ... + 1491853.

It is an arithmetic number, because the mean of its divisors is an integer number (50720758).

Almost surely, 2^199899391 is an apocalyptic number.

199899391 is a deficient number, since it is larger than the sum of its proper divisors (2983641).

199899391 is an equidigital number, since it uses as much as digits as its factorization.

199899391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2983640.

The product of its digits is 1417176, while the sum is 58.

The square root of 199899391 is about 14138.5781109700. The cubic root of 199899391 is about 584.7054703614.

The spelling of 199899391 in words is "one hundred ninety-nine million, eight hundred ninety-nine thousand, three hundred ninety-one".