9906521 has 4 divisors (see below), whose sum is σ = 10032000. Its totient is φ = 9781044.

The previous prime is 9906517. The next prime is 9906527. The reversal of 9906521 is 1256099.

9906521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9906521 - 2² = 9906517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9906527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62621 + ... + 62778.

It is an arithmetic number, because the mean of its divisors is an integer number (2508000).

Almost surely, 2^9906521 is an apocalyptic number.

It is an amenable number.

9906521 is a deficient number, since it is larger than the sum of its proper divisors (125479).

9906521 is a wasteful number, since it uses less digits than its factorization.

9906521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125478.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 9906521 is about 3147.4626288488. The cubic root of 9906521 is about 214.7700516097.

The spelling of 9906521 in words is "nine million, nine hundred six thousand, five hundred twenty-one".