199887791 has 8 divisors (see below), whose sum is σ = 204259968. Its totient is φ = 195559000.

The previous prime is 199887761. The next prime is 199887817. The reversal of 199887791 is 197788991.

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 199887791 - 2¹⁴ = 199871407 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 199887791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199887731) 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 in 7 ways as a sum of consecutive naturals, for example, 1445 + ... + 20046.

It is an arithmetic number, because the mean of its divisors is an integer number (25532496).

Almost surely, 2^199887791 is an apocalyptic number.

199887791 is a deficient number, since it is larger than the sum of its proper divisors (4372177).

199887791 is a wasteful number, since it uses less digits than its factorization.

199887791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21693.

The product of its digits is 2286144, while the sum is 59.

The square root of 199887791 is about 14138.1678798917. The cubic root of 199887791 is about 584.6941601475.

The spelling of 199887791 in words is "one hundred ninety-nine million, eight hundred eighty-seven thousand, seven hundred ninety-one".