9991111213 has 4 divisors (see below), whose sum is σ = 10032568348. Its totient is φ = 9949654080.

The previous prime is 9991111187. The next prime is 9991111223. The reversal of 9991111213 is 3121111999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3121111999 = 101 ⋅30902099.

It can be written as a sum of positive squares in 2 ways, for example, as 7911568809 + 2079542404 = 88947^2 + 45602^2 .

It is a cyclic number.

It is not a de Polignac number, because 9991111213 - 2⁵ = 9991111181 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 (9991111223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20728206 + ... + 20728687.

It is an arithmetic number, because the mean of its divisors is an integer number (2508142087).

Almost surely, 2^9991111213 is an apocalyptic number.

It is an amenable number.

9991111213 is a deficient number, since it is larger than the sum of its proper divisors (41457135).

9991111213 is a wasteful number, since it uses less digits than its factorization.

9991111213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41457134.

The product of its digits is 4374, while the sum is 37.

The square root of 9991111213 is about 99955.5461842913. The cubic root of 9991111213 is about 2153.7961570996.

The spelling of 9991111213 in words is "nine billion, nine hundred ninety-one million, one hundred eleven thousand, two hundred thirteen".