2221222221 has 24 divisors (see below), whose sum is σ = 3297716760. Its totient is φ = 1439669376.

The previous prime is 2221222207. The next prime is 2221222229. The reversal of 2221222221 is 1222221222.

2221222221 is a `hidden beast` number, since 2 + 221 + 222 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 961682121 + 1259540100 = 31011^2 + 35490^2 .

It is not a de Polignac number, because 2221222221 - 2³¹ = 73738573 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2221222194 and 2221222203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2221222229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 762115 + ... + 765023.

It is an arithmetic number, because the mean of its divisors is an integer number (137404865).

Almost surely, 2^2221222221 is an apocalyptic number.

It is an amenable number.

2221222221 is a deficient number, since it is larger than the sum of its proper divisors (1076494539).

2221222221 is a wasteful number, since it uses less digits than its factorization.

2221222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5245 (or 5242 counting only the distinct ones).

The product of its digits is 256, while the sum is 18.

The square root of 2221222221 is about 47129.8442709076. The cubic root of 2221222221 is about 1304.7601073994.

Adding to 2221222221 its reverse (1222221222), we get a palindrome (3443443443).

Subtracting from 2221222221 its reverse (1222221222), we obtain a palindrome (999000999).

The spelling of 2221222221 in words is "two billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty-one".