644464727 has 2 divisors, whose sum is σ = 644464728. Its totient is φ = 644464726.

The previous prime is 644464721. The next prime is 644464757. The reversal of 644464727 is 727464446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644464727 - 2⁶ = 644464663 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644464721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322232363 + 322232364.

It is an arithmetic number, because the mean of its divisors is an integer number (322232364).

Almost surely, 2^644464727 is an apocalyptic number.

644464727 is a deficient number, since it is larger than the sum of its proper divisors (1).

644464727 is an equidigital number, since it uses as much as digits as its factorization.

644464727 is an evil number, because the sum of its binary digits is even.

The product of its digits is 903168, while the sum is 44.

The square root of 644464727 is about 25386.3098342394. The cubic root of 644464727 is about 863.7731846144.

The spelling of 644464727 in words is "six hundred forty-four million, four hundred sixty-four thousand, seven hundred twenty-seven".