2128221 has 8 divisors (see below), whose sum is σ = 3152960. Its totient is φ = 1418796.

The previous prime is 2128201. The next prime is 2128241. The reversal of 2128221 is 1228212.

It is a happy number.

2128221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (2128201) and next prime (2128241).

It is not a de Polignac number, because 2128221 - 2⁶ = 2128157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2128194 and 2128203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2128201) 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 7 ways as a sum of consecutive naturals, for example, 39385 + ... + 39438.

It is an arithmetic number, because the mean of its divisors is an integer number (394120).

2^2128221 is an apocalyptic number.

It is an amenable number.

2128221 is a deficient number, since it is larger than the sum of its proper divisors (1024739).

2128221 is an equidigital number, since it uses as much as digits as its factorization.

2128221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78832 (or 78826 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 2128221 is about 1458.8423492619. The cubic root of 2128221 is about 128.6290043718.

Subtracting from 2128221 its reverse (1228212), we obtain a palindrome (900009).

The spelling of 2128221 in words is "two million, one hundred twenty-eight thousand, two hundred twenty-one".