1122222221 has 2 divisors, whose sum is σ = 1122222222. Its totient is φ = 1122222220.

The previous prime is 1122222217. The next prime is 1122222223. The reversal of 1122222221 is 1222222211.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 856206121 + 266016100 = 29261^2 + 16310^2 .

It is a cyclic number.

It is not a de Polignac number, because 1122222221 - 2² = 1122222217 is a prime.

Together with 1122222223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1122222221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1122222223) 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 as a sum of consecutive naturals, namely, 561111110 + 561111111.

It is an arithmetic number, because the mean of its divisors is an integer number (561111111).

Almost surely, 2^1122222221 is an apocalyptic number.

It is an amenable number.

1122222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1122222221 is an equidigital number, since it uses as much as digits as its factorization.

1122222221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 17.

The square root of 1122222221 is about 33499.5853854940. The cubic root of 1122222221 is about 1039.1852040793.

Adding to 1122222221 its reverse (1222222211), we get a palindrome (2344444432).

The spelling of 1122222221 in words is "one billion, one hundred twenty-two million, two hundred twenty-two thousand, two hundred twenty-one".