9991324799 has 4 divisors (see below), whose sum is σ = 10128192336. Its totient is φ = 9854457264.

The previous prime is 9991324787. The next prime is 9991324801. The reversal of 9991324799 is 9974231999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9991324799 is a prime.

It is a super-2 number, since 2×9991324799² (a number of 21 digits) contains 22 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 (9991314799) 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, 68433659 + ... + 68433804.

It is an arithmetic number, because the mean of its divisors is an integer number (2532048084).

Almost surely, 2^9991324799 is an apocalyptic number.

9991324799 is a deficient number, since it is larger than the sum of its proper divisors (136867537).

9991324799 is a wasteful number, since it uses less digits than its factorization.

9991324799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136867536.

The product of its digits is 9920232, while the sum is 62.

The square root of 9991324799 is about 99956.6145835282. The cubic root of 9991324799 is about 2153.8115046559.

The spelling of 9991324799 in words is "nine billion, nine hundred ninety-one million, three hundred twenty-four thousand, seven hundred ninety-nine".