9900521 has 4 divisors (see below), whose sum is σ = 9941844. Its totient is φ = 9859200.

The previous prime is 9900509. The next prime is 9900529. The reversal of 9900521 is 1250099.

It is a happy number.

9900521 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.

It can be written as a sum of positive squares in 2 ways, for example, as 5856400 + 4044121 = 2420^2 + 2011^2 .

It is a cyclic number.

It is not a de Polignac number, because 9900521 - 2¹⁰ = 9899497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9900529) 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, 20300 + ... + 20781.

It is an arithmetic number, because the mean of its divisors is an integer number (2485461).

Almost surely, 2^9900521 is an apocalyptic number.

It is an amenable number.

9900521 is a deficient number, since it is larger than the sum of its proper divisors (41323).

9900521 is a wasteful number, since it uses less digits than its factorization.

9900521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41322.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 9900521 is about 3146.5093357561. The cubic root of 9900521 is about 214.7266835240.

The spelling of 9900521 in words is "nine million, nine hundred thousand, five hundred twenty-one".