9991324756 has 48 divisors (see below), whose sum is σ = 20211206400. Its totient is φ = 4233120768.

The previous prime is 9991324753. The next prime is 9991324757. The reversal of 9991324756 is 6574231999.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 9991324697 and 9991324706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991324751) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3581010 + ... + 3583798.

It is an arithmetic number, because the mean of its divisors is an integer number (421066800).

Almost surely, 2^9991324756 is an apocalyptic number.

It is an amenable number.

9991324756 is an abundant number, since it is smaller than the sum of its proper divisors (10219881644).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9991324756 is a wasteful number, since it uses less digits than its factorization.

9991324756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4216 (or 4214 counting only the distinct ones).

The product of its digits is 3674160, while the sum is 55.

The square root of 9991324756 is about 99956.6143684349. The cubic root of 9991324756 is about 2153.8115015661.

The spelling of 9991324756 in words is "nine billion, nine hundred ninety-one million, three hundred twenty-four thousand, seven hundred fifty-six".