2152211221 has 4 divisors (see below), whose sum is σ = 2171257452. Its totient is φ = 2133164992.

The previous prime is 2152211219. The next prime is 2152211251. The reversal of 2152211221 is 1221122512.

It is a happy number.

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 385690321 + 1766520900 = 19639^2 + 42030^2 .

It is a cyclic number.

It is not a de Polignac number, because 2152211221 - 2¹ = 2152211219 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 (2152211251) 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, 9522946 + ... + 9523171.

It is an arithmetic number, because the mean of its divisors is an integer number (542814363).

Almost surely, 2^2152211221 is an apocalyptic number.

It is an amenable number.

2152211221 is a deficient number, since it is larger than the sum of its proper divisors (19046231).

2152211221 is a wasteful number, since it uses less digits than its factorization.

2152211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19046230.

The product of its digits is 160, while the sum is 19.

The square root of 2152211221 is about 46391.9305590962. The cubic root of 2152211221 is about 1291.1052005224.

Adding to 2152211221 its reverse (1221122512), we get a palindrome (3373333733).

The spelling of 2152211221 in words is "two billion, one hundred fifty-two million, two hundred eleven thousand, two hundred twenty-one".