12644561 has 2 divisors, whose sum is σ = 12644562. Its totient is φ = 12644560.

The previous prime is 12644483. The next prime is 12644563. The reversal of 12644561 is 16544621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11730625 + 913936 = 3425^2 + 956^2 .

It is a cyclic number.

It is not a de Polignac number, because 12644561 - 2¹⁸ = 12382417 is a prime.

Together with 12644563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (12644563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6322280 + 6322281.

It is an arithmetic number, because the mean of its divisors is an integer number (6322281).

Almost surely, 2^12644561 is an apocalyptic number.

It is an amenable number.

12644561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12644561 is an equidigital number, since it uses as much as digits as its factorization.

12644561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 29.

The square root of 12644561 is about 3555.9191498120. The cubic root of 12644561 is about 232.9706717677.

The spelling of 12644561 in words is "twelve million, six hundred forty-four thousand, five hundred sixty-one".