9991944000 has 448 divisors, whose sum is σ = 37011985920. Its totient is φ = 2639001600.

The previous prime is 9991943993. The next prime is 9991944007. The reversal of 9991944000 is 4491999.

It is an interprime number because it is at equal distance from previous prime (9991943993) and next prime (9991944007).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991944007) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 36071862 + ... + 36072138.

It is an arithmetic number, because the mean of its divisors is an integer number (82616040).

Almost surely, 2^9991944000 is an apocalyptic number.

9991944000 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9991944000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18505992960).

9991944000 is an abundant number, since it is smaller than the sum of its proper divisors (27020041920).

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

9991944000 is a wasteful number, since it uses less digits than its factorization.

9991944000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480 (or 454 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 9991944000 is about 99959.7118843387. The cubic root of 9991944000 is about 2153.8559970769.

The spelling of 9991944000 in words is "nine billion, nine hundred ninety-one million, nine hundred forty-four thousand".