1111121021 has 2 divisors, whose sum is σ = 1111121022. Its totient is φ = 1111121020.

The previous prime is 1111120957. The next prime is 1111121023. The reversal of 1111121021 is 1201211111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 689640121 + 421480900 = 26261^2 + 20530^2 .

It is an emirp because it is prime and its reverse (1201211111) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1111121021 - 2⁶ = 1111120957 is a prime.

Together with 1111121023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1111120993 and 1111121011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1111121023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 555560510 + 555560511.

It is an arithmetic number, because the mean of its divisors is an integer number (555560511).

Almost surely, 2^1111121021 is an apocalyptic number.

It is an amenable number.

1111121021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1111121021 is an equidigital number, since it uses as much as digits as its factorization.

1111121021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 11.

The square root of 1111121021 is about 33333.4819813352. The cubic root of 1111121021 is about 1035.7472478750.

Adding to 1111121021 its reverse (1201211111), we get a palindrome (2312332132).

The spelling of 1111121021 in words is "one billion, one hundred eleven million, one hundred twenty-one thousand, twenty-one".