991323199 has 4 divisors (see below), whose sum is σ = 1003266936. Its totient is φ = 979379464.

The previous prime is 991323197. The next prime is 991323209.

991323199 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 991323199 - 2¹ = 991323197 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 (991323197) 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 3 ways as a sum of consecutive naturals, for example, 5971744 + ... + 5971909.

It is an arithmetic number, because the mean of its divisors is an integer number (250816734).

Almost surely, 2^991323199 is an apocalyptic number.

991323199 is a deficient number, since it is larger than the sum of its proper divisors (11943737).

991323199 is a wasteful number, since it uses less digits than its factorization.

991323199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11943736.

The product of its digits is 118098, while the sum is 46.

The square root of 991323199 is about 31485.2854362161. The cubic root of 991323199 is about 997.0993272328.

The spelling of 991323199 in words is "nine hundred ninety-one million, three hundred twenty-three thousand, one hundred ninety-nine".