2121221 has 4 divisors (see below), whose sum is σ = 2213472. Its totient is φ = 2028972.

The previous prime is 2121199. The next prime is 2121239. The reversal of 2121221 is 1221212.

It is a happy number.

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-2121221 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 (2121241) 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, 46091 + ... + 46136.

It is an arithmetic number, because the mean of its divisors is an integer number (553368).

2^2121221 is an apocalyptic number.

It is an amenable number.

2121221 is a deficient number, since it is larger than the sum of its proper divisors (92251).

2121221 is an equidigital number, since it uses as much as digits as its factorization.

2121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92250.

The product of its digits is 16, while the sum is 11.

The square root of 2121221 is about 1456.4412106227. The cubic root of 2121221 is about 128.4878235420.

Adding to 2121221 its reverse (1221212), we get a palindrome (3342433).

Subtracting from 2121221 its reverse (1221212), we obtain a palindrome (900009).

It can be divided in two parts, 212 and 1221, that multiplied together give a palindrome (258852).

The spelling of 2121221 in words is "two million, one hundred twenty-one thousand, two hundred twenty-one".