12421021 has 2 divisors, whose sum is σ = 12421022. Its totient is φ = 12421020.

The previous prime is 12421009. The next prime is 12421037. The reversal of 12421021 is 12012421.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11655396 + 765625 = 3414^2 + 875^2 .

It is a cyclic number.

It is not a de Polignac number, because 12421021 - 2¹⁵ = 12388253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12420992 and 12421010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12421051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6210510 + 6210511.

It is an arithmetic number, because the mean of its divisors is an integer number (6210511).

Almost surely, 2^12421021 is an apocalyptic number.

It is an amenable number.

12421021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12421021 is an equidigital number, since it uses as much as digits as its factorization.

12421021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 12421021 is about 3524.3468898507. The cubic root of 12421021 is about 231.5896245612.

Adding to 12421021 its reverse (12012421), we get a palindrome (24433442).

The spelling of 12421021 in words is "twelve million, four hundred twenty-one thousand, twenty-one".