9921888 has 72 divisors (see below), whose sum is σ = 28855008. Its totient is φ = 3232512.

The previous prime is 9921869. The next prime is 9921889. The reversal of 9921888 is 8881299.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×9921888² = 196887722969088, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9921889) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 13170 + ... + 13902.

It is an arithmetic number, because the mean of its divisors is an integer number (400764).

Almost surely, 2^9921888 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 9921888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14427504).

9921888 is an abundant number, since it is smaller than the sum of its proper divisors (18933120).

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

9921888 is a wasteful number, since it uses less digits than its factorization.

9921888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796 (or 785 counting only the distinct ones).

The product of its digits is 82944, while the sum is 45.

The square root of 9921888 is about 3149.9028556449. The cubic root of 9921888 is about 214.8810447067.

The spelling of 9921888 in words is "nine million, nine hundred twenty-one thousand, eight hundred eighty-eight".