12664021 has 2 divisors, whose sum is σ = 12664022. Its totient is φ = 12664020.

The previous prime is 12664019. The next prime is 12664033. The reversal of 12664021 is 12046621.

12664021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11464996 + 1199025 = 3386^2 + 1095^2 .

It is a cyclic number.

It is not a de Polignac number, because 12664021 - 2¹ = 12664019 is a prime.

Together with 12664019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 12663983 and 12664001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12664061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6332010 + 6332011.

It is an arithmetic number, because the mean of its divisors is an integer number (6332011).

Almost surely, 2^12664021 is an apocalyptic number.

It is an amenable number.

12664021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12664021 is an equidigital number, since it uses as much as digits as its factorization.

12664021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 12664021 is about 3558.6543805208. The cubic root of 12664021 is about 233.0901245905.

The spelling of 12664021 in words is "twelve million, six hundred sixty-four thousand, twenty-one".