644568299 has 2 divisors, whose sum is σ = 644568300. Its totient is φ = 644568298.

The previous prime is 644568271. The next prime is 644568329. The reversal of 644568299 is 992865446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644568299 - 2¹⁶ = 644502763 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644568299.

It is not a weakly prime, because it can be changed into another prime (644568259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322284149 + 322284150.

It is an arithmetic number, because the mean of its divisors is an integer number (322284150).

Almost surely, 2^644568299 is an apocalyptic number.

644568299 is a deficient number, since it is larger than the sum of its proper divisors (1).

644568299 is an equidigital number, since it uses as much as digits as its factorization.

644568299 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3732480, while the sum is 53.

The square root of 644568299 is about 25388.3496706659. The cubic root of 644568299 is about 863.8194544982.

The spelling of 644568299 in words is "six hundred forty-four million, five hundred sixty-eight thousand, two hundred ninety-nine".