9991872 has 168 divisors, whose sum is σ = 33284160. Its totient is φ = 2833920.

The previous prime is 9991847. The next prime is 9991879. The reversal of 9991872 is 2781999.

It is not an unprimeable number, because it can be changed into a prime (9991879) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120343 + ... + 120425.

It is an arithmetic number, because the mean of its divisors is an integer number (198120).

Almost surely, 2^9991872 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 9991872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16642080).

9991872 is an abundant number, since it is smaller than the sum of its proper divisors (23292288).

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

9991872 is a wasteful number, since it uses less digits than its factorization.

9991872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 118 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 9991872 is about 3160.9922492787. The cubic root of 9991872 is about 215.3850823642.

The spelling of 9991872 in words is "nine million, nine hundred ninety-one thousand, eight hundred seventy-two".