9981664 has 48 divisors (see below), whose sum is σ = 24506496. Its totient is φ = 3888000.

The previous prime is 9981661. The next prime is 9981689. The reversal of 9981664 is 4661899.

It is a self number, because there is not a number n which added to its sum of digits gives 9981664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9981661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 439 + ... + 4489.

It is an arithmetic number, because the mean of its divisors is an integer number (510552).

Almost surely, 2^9981664 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 9981664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12253248).

9981664 is an abundant number, since it is smaller than the sum of its proper divisors (14524832).

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

9981664 is a wasteful number, since it uses less digits than its factorization.

9981664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4079 (or 4071 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 9981664 is about 3159.3771538074. The cubic root of 9981664 is about 215.3117093906.

It can be divided in two parts, 998 and 1664, that added together give a palindrome (2662).

The spelling of 9981664 in words is "nine million, nine hundred eighty-one thousand, six hundred sixty-four".