644296319 has 2 divisors, whose sum is σ = 644296320. Its totient is φ = 644296318.

The previous prime is 644296291. The next prime is 644296333. The reversal of 644296319 is 913692446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644296319 - 2⁸ = 644296063 is a prime.

It is a super-2 number, since 2×644296319² = 830235493353899522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644296319.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644296819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322148159 + 322148160.

It is an arithmetic number, because the mean of its divisors is an integer number (322148160).

Almost surely, 2^644296319 is an apocalyptic number.

644296319 is a deficient number, since it is larger than the sum of its proper divisors (1).

644296319 is an equidigital number, since it uses as much as digits as its factorization.

644296319 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 44.

The square root of 644296319 is about 25382.9927116564. The cubic root of 644296319 is about 863.6979392306.

The spelling of 644296319 in words is "six hundred forty-four million, two hundred ninety-six thousand, three hundred nineteen".