1111222121 has 2 divisors, whose sum is σ = 1111222122. Its totient is φ = 1111222120.

The previous prime is 1111222117. The next prime is 1111222141. The reversal of 1111222121 is 1212221111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 616826896 + 494395225 = 24836^2 + 22235^2 .

It is a cyclic number.

It is not a de Polignac number, because 1111222121 - 2² = 1111222117 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1111222096 and 1111222105.

It is not a weakly prime, because it can be changed into another prime (1111222141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 555611060 + 555611061.

It is an arithmetic number, because the mean of its divisors is an integer number (555611061).

Almost surely, 2^1111222121 is an apocalyptic number.

It is an amenable number.

1111222121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1111222121 is an equidigital number, since it uses as much as digits as its factorization.

1111222121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16, while the sum is 14.

The square root of 1111222121 is about 33334.9984400780. The cubic root of 1111222121 is about 1035.7786608561.

Adding to 1111222121 its reverse (1212221111), we get a palindrome (2323443232).

It can be divided in two parts, 11112 and 22121, that added together give a palindrome (33233).

The spelling of 1111222121 in words is "one billion, one hundred eleven million, two hundred twenty-two thousand, one hundred twenty-one".