644669747 has 2 divisors, whose sum is σ = 644669748. Its totient is φ = 644669746.

The previous prime is 644669741. The next prime is 644669771. The reversal of 644669747 is 747966446.

644669747 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 is a cyclic number.

It is not a de Polignac number, because 644669747 - 2¹⁶ = 644604211 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644669741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322334873 + 322334874.

It is an arithmetic number, because the mean of its divisors is an integer number (322334874).

Almost surely, 2^644669747 is an apocalyptic number.

644669747 is a deficient number, since it is larger than the sum of its proper divisors (1).

644669747 is an equidigital number, since it uses as much as digits as its factorization.

644669747 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6096384, while the sum is 53.

The square root of 644669747 is about 25390.3475163299. The cubic root of 644669747 is about 863.8647706988.

The spelling of 644669747 in words is "six hundred forty-four million, six hundred sixty-nine thousand, seven hundred forty-seven".