121231021 has 2 divisors, whose sum is σ = 121231022. Its totient is φ = 121231020.

The previous prime is 121231013. The next prime is 121231031. The reversal of 121231021 is 120132121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115326121 + 5904900 = 10739^2 + 2430^2 .

It is a cyclic number.

It is not a de Polignac number, because 121231021 - 2³ = 121231013 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 121230992 and 121231010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121231031) 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, 60615510 + 60615511.

It is an arithmetic number, because the mean of its divisors is an integer number (60615511).

Almost surely, 2^121231021 is an apocalyptic number.

It is an amenable number.

121231021 is a deficient number, since it is larger than the sum of its proper divisors (1).

121231021 is an equidigital number, since it uses as much as digits as its factorization.

121231021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 121231021 is about 11010.4959470498. The cubic root of 121231021 is about 494.9233238374.

Adding to 121231021 its reverse (120132121), we get a palindrome (241363142).

The spelling of 121231021 in words is "one hundred twenty-one million, two hundred thirty-one thousand, twenty-one".