991323 has 12 divisors (see below), whose sum is σ = 1494480. Its totient is φ = 632016.

The previous prime is 991313. The next prime is 991327. The reversal of 991323 is 323199.

991323 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 991323 - 2¹² = 987227 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991323.

It is not an unprimeable number, because it can be changed into a prime (991327) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2188 + ... + 2601.

It is an arithmetic number, because the mean of its divisors is an integer number (124540).

2⁹⁹¹³²³ is an apocalyptic number.

991323 is a deficient number, since it is larger than the sum of its proper divisors (503157).

991323 is a wasteful number, since it uses less digits than its factorization.

991323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4818 (or 4815 counting only the distinct ones).

The product of its digits is 1458, while the sum is 27.

The square root of 991323 is about 995.6520476552. The cubic root of 991323 is about 99.7099260513.

The spelling of 991323 in words is "nine hundred ninety-one thousand, three hundred twenty-three".