9991521792 has 720 divisors, whose sum is σ = 37659576240. Its totient is φ = 2526806016.

The previous prime is 9991521781. The next prime is 9991521803. The reversal of 9991521792 is 2971251999.

It is an interprime number because it is at equal distance from previous prime (9991521781) and next prime (9991521803).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 72930748 + ... + 72930884.

It is an arithmetic number, because the mean of its divisors is an integer number (52304967).

Almost surely, 2^9991521792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9991521792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18829788120).

9991521792 is an abundant number, since it is smaller than the sum of its proper divisors (27668054448).

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

9991521792 is a wasteful number, since it uses less digits than its factorization.

9991521792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211 (or 185 counting only the distinct ones).

The product of its digits is 918540, while the sum is 54.

The square root of 9991521792 is about 99957.5999711878. The cubic root of 9991521792 is about 2153.8256597024.

The spelling of 9991521792 in words is "nine billion, nine hundred ninety-one million, five hundred twenty-one thousand, seven hundred ninety-two".