199988191 has 8 divisors (see below), whose sum is σ = 217279440. Its totient is φ = 182969472.

The previous prime is 199988179. The next prime is 199988207. The reversal of 199988191 is 191889991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 199988191 - 2¹³ = 199979999 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 (199988291) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66601 + ... + 69538.

It is an arithmetic number, because the mean of its divisors is an integer number (27159930).

Almost surely, 2^199988191 is an apocalyptic number.

199988191 is a deficient number, since it is larger than the sum of its proper divisors (17291249).

199988191 is a wasteful number, since it uses less digits than its factorization.

199988191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136265.

The product of its digits is 419904, while the sum is 55.

The square root of 199988191 is about 14141.7181063688. The cubic root of 199988191 is about 584.7920375075.

The spelling of 199988191 in words is "one hundred ninety-nine million, nine hundred eighty-eight thousand, one hundred ninety-one".