12644721 has 8 divisors (see below), whose sum is σ = 18732960. Its totient is φ = 8429796.

The previous prime is 12644707. The next prime is 12644741. The reversal of 12644721 is 12744621.

12644721 is a `hidden beast` number, since 12 + 644 + 7 + 2 + 1 = 666.

It is not a de Polignac number, because 12644721 - 2¹³ = 12636529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 468323 = 12644721 / (1 + 2 + 6 + 4 + 4 + 7 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (12644701) 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 in 7 ways as a sum of consecutive naturals, for example, 234135 + ... + 234188.

It is an arithmetic number, because the mean of its divisors is an integer number (2341620).

Almost surely, 2^12644721 is an apocalyptic number.

It is an amenable number.

12644721 is a deficient number, since it is larger than the sum of its proper divisors (6088239).

12644721 is an equidigital number, since it uses as much as digits as its factorization.

12644721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 468332 (or 468326 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 12644721 is about 3555.9416474402. The cubic root of 12644721 is about 232.9716544076.

The spelling of 12644721 in words is "twelve million, six hundred forty-four thousand, seven hundred twenty-one".