9999020221 has 4 divisors (see below), whose sum is σ = 10168495200. Its totient is φ = 9829545244.

The previous prime is 9999020197. The next prime is 9999020231. The reversal of 9999020221 is 1220209999.

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 9999020221 - 2⁵ = 9999020189 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 (9999020231) 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, 84737401 + ... + 84737518.

It is an arithmetic number, because the mean of its divisors is an integer number (2542123800).

Almost surely, 2^9999020221 is an apocalyptic number.

It is an amenable number.

9999020221 is a deficient number, since it is larger than the sum of its proper divisors (169474979).

9999020221 is a wasteful number, since it uses less digits than its factorization.

9999020221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169474978.

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 9999020221 is about 99995.1009849983. The cubic root of 9999020221 is about 2154.3643254049.

The spelling of 9999020221 in words is "nine billion, nine hundred ninety-nine million, twenty thousand, two hundred twenty-one".