9876521 has 4 divisors (see below), whose sum is σ = 10143492. Its totient is φ = 9609552.

The previous prime is 9876511. The next prime is 9876527. The reversal of 9876521 is 1256789.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8410000 + 1466521 = 2900^2 + 1211^2 .

It is a cyclic number.

It is not a de Polignac number, because 9876521 - 2²² = 5682217 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9876527) 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 3 ways as a sum of consecutive naturals, for example, 133430 + ... + 133503.

It is an arithmetic number, because the mean of its divisors is an integer number (2535873).

Almost surely, 2^9876521 is an apocalyptic number.

It is an amenable number.

9876521 is a deficient number, since it is larger than the sum of its proper divisors (266971).

9876521 is a wasteful number, since it uses less digits than its factorization.

9876521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266970.

The product of its digits is 30240, while the sum is 38.

The square root of 9876521 is about 3142.6932717018. The cubic root of 9876521 is about 214.5530357534.

The spelling of 9876521 in words is "nine million, eight hundred seventy-six thousand, five hundred twenty-one".