199444991 has 4 divisors (see below), whose sum is σ = 201015552. Its totient is φ = 197874432.

The previous prime is 199444913. The next prime is 199445009.

199444991 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199444991 - 2¹⁸ = 199182847 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 (199444291) 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, 785090 + ... + 785343.

It is an arithmetic number, because the mean of its divisors is an integer number (50253888).

Almost surely, 2^199444991 is an apocalyptic number.

199444991 is a deficient number, since it is larger than the sum of its proper divisors (1570561).

199444991 is a wasteful number, since it uses less digits than its factorization.

199444991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1570560.

The product of its digits is 419904, while the sum is 50.

The square root of 199444991 is about 14122.4994600814. The cubic root of 199444991 is about 584.2620944273.

The spelling of 199444991 in words is "one hundred ninety-nine million, four hundred forty-four thousand, nine hundred ninety-one".