199404991 has 4 divisors (see below), whose sum is σ = 202213584. Its totient is φ = 196596400.

The previous prime is 199404983. The next prime is 199405001.

199404991 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 199404991 - 2³ = 199404983 is a prime.

It is a super-3 number, since 3×199404991³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199404971) 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, 1404190 + ... + 1404331.

It is an arithmetic number, because the mean of its divisors is an integer number (50553396).

Almost surely, 2^199404991 is an apocalyptic number.

199404991 is a deficient number, since it is larger than the sum of its proper divisors (2808593).

199404991 is an equidigital number, since it uses as much as digits as its factorization.

199404991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2808592.

The product of its (nonzero) digits is 104976, while the sum is 46.

The square root of 199404991 is about 14121.0832091593. The cubic root of 199404991 is about 584.2230326185.

The spelling of 199404991 in words is "one hundred ninety-nine million, four hundred four thousand, nine hundred ninety-one".