9897921 has 36 divisors (see below), whose sum is σ = 16079700. Its totient is φ = 5860800.

The previous prime is 9897919. The next prime is 9897929. The reversal of 9897921 is 1297989.

9897921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 680625 + 9217296 = 825^2 + 3036^2 .

It is not a de Polignac number, because 9897921 - 2¹ = 9897919 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9897929) 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 35 ways as a sum of consecutive naturals, for example, 66355 + ... + 66503.

Almost surely, 2^9897921 is an apocalyptic number.

It is an amenable number.

9897921 is a deficient number, since it is larger than the sum of its proper divisors (6181779).

9897921 is a wasteful number, since it uses less digits than its factorization.

9897921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238 (or 224 counting only the distinct ones).

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

The square root of 9897921 is about 3146.0961523768. The cubic root of 9897921 is about 214.7078852454.

The spelling of 9897921 in words is "nine million, eight hundred ninety-seven thousand, nine hundred twenty-one".