12421681 has 2 divisors, whose sum is σ = 12421682. Its totient is φ = 12421680.

The previous prime is 12421639. The next prime is 12421691. The reversal of 12421681 is 18612421.

12421681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11451456 + 970225 = 3384^2 + 985^2 .

It is a cyclic number.

It is not a de Polignac number, because 12421681 - 2⁷ = 12421553 is a prime.

It is a super-2 number, since 2×12421681² = 308596317731522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (12421601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6210840 + 6210841.

It is an arithmetic number, because the mean of its divisors is an integer number (6210841).

Almost surely, 2^12421681 is an apocalyptic number.

It is an amenable number.

12421681 is a deficient number, since it is larger than the sum of its proper divisors (1).

12421681 is an equidigital number, since it uses as much as digits as its factorization.

12421681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 25.

The square root of 12421681 is about 3524.4405229767. The cubic root of 12421681 is about 231.5937263830.

It can be divided in two parts, 1242 and 1681, that multiplied together give a palindrome (2087802).

The spelling of 12421681 in words is "twelve million, four hundred twenty-one thousand, six hundred eighty-one".