9900221 has 4 divisors (see below), whose sum is σ = 10110912. Its totient is φ = 9689532.

The previous prime is 9900203. The next prime is 9900251. The reversal of 9900221 is 1220099.

9900221 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 a de Polignac number, because none of the positive numbers 2^k-9900221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9900251) 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, 105275 + ... + 105368.

It is an arithmetic number, because the mean of its divisors is an integer number (2527728).

Almost surely, 2^9900221 is an apocalyptic number.

It is an amenable number.

9900221 is a deficient number, since it is larger than the sum of its proper divisors (210691).

9900221 is a wasteful number, since it uses less digits than its factorization.

9900221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210690.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 9900221 is about 3146.4616635198. The cubic root of 9900221 is about 214.7245146599.

The spelling of 9900221 in words is "nine million, nine hundred thousand, two hundred twenty-one".