644646487 has 2 divisors, whose sum is σ = 644646488. Its totient is φ = 644646486.

The previous prime is 644646479. The next prime is 644646493. The reversal of 644646487 is 784646446.

644646487 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 is a cyclic number.

It is not a de Polignac number, because 644646487 - 2³ = 644646479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644646487.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644646427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322323243 + 322323244.

It is an arithmetic number, because the mean of its divisors is an integer number (322323244).

Almost surely, 2^644646487 is an apocalyptic number.

644646487 is a deficient number, since it is larger than the sum of its proper divisors (1).

644646487 is an equidigital number, since it uses as much as digits as its factorization.

644646487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3096576, while the sum is 49.

The square root of 644646487 is about 25389.8894641154. The cubic root of 644646487 is about 863.8543810192.

The spelling of 644646487 in words is "six hundred forty-four million, six hundred forty-six thousand, four hundred eighty-seven".