199995891 has 8 divisors (see below), whose sum is σ = 266986944. Its totient is φ = 133167720.

The previous prime is 199995889. The next prime is 199995923. The reversal of 199995891 is 198599991.

It is a happy number.

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

It is not a de Polignac number, because 199995891 - 2¹ = 199995889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (199995811) 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 7 ways as a sum of consecutive naturals, for example, 37825 + ... + 42786.

It is an arithmetic number, because the mean of its divisors is an integer number (33373368).

Almost surely, 2^199995891 is an apocalyptic number.

199995891 is a deficient number, since it is larger than the sum of its proper divisors (66991053).

199995891 is an equidigital number, since it uses as much as digits as its factorization.

199995891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81441.

The product of its digits is 2361960, while the sum is 60.

The square root of 199995891 is about 14141.9903478966. The cubic root of 199995891 is about 584.7995426855.

The spelling of 199995891 in words is "one hundred ninety-nine million, nine hundred ninety-five thousand, eight hundred ninety-one".