991211323 has 4 divisors (see below), whose sum is σ = 1043380360. Its totient is φ = 939042288.

The previous prime is 991211321. The next prime is 991211327. The reversal of 991211323 is 323112199.

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 991211323 - 2¹ = 991211321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991211321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26084490 + ... + 26084527.

It is an arithmetic number, because the mean of its divisors is an integer number (260845090).

Almost surely, 2^991211323 is an apocalyptic number.

991211323 is a deficient number, since it is larger than the sum of its proper divisors (52169037).

991211323 is a wasteful number, since it uses less digits than its factorization.

991211323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52169036.

The product of its digits is 2916, while the sum is 31.

The square root of 991211323 is about 31483.5087466439. The cubic root of 991211323 is about 997.0618165330.

The spelling of 991211323 in words is "nine hundred ninety-one million, two hundred eleven thousand, three hundred twenty-three".