121021 has 2 divisors, whose sum is σ = 121022. Its totient is φ = 121020.

The previous prime is 121019. The next prime is 121039. The reversal of 121021 is 120121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68121 + 52900 = 261^2 + 230^2 .

It is an emirp because it is prime and its reverse (120121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121021 - 2¹ = 121019 is a prime.

Together with 121019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 120995 and 121013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60510 + 60511.

It is an arithmetic number, because the mean of its divisors is an integer number (60511).

2¹²¹⁰²¹ is an apocalyptic number.

It is an amenable number.

121021 is a deficient number, since it is larger than the sum of its proper divisors (1).

121021 is an equidigital number, since it uses as much as digits as its factorization.

121021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 121021 is about 347.8807266866. The cubic root of 121021 is about 49.4637356399.

Adding to 121021 its reverse (120121), we get a palindrome (241142).

Subtracting from 121021 its reverse (120121), we obtain a square (900 = 30²).

The spelling of 121021 in words is "one hundred twenty-one thousand, twenty-one", and thus it is an iban number.