644466079 has 2 divisors, whose sum is σ = 644466080. Its totient is φ = 644466078.

The previous prime is 644466047. The next prime is 644466083. The reversal of 644466079 is 970664446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644466079 - 2⁵ = 644466047 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644466479) 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, 322233039 + 322233040.

It is an arithmetic number, because the mean of its divisors is an integer number (322233040).

Almost surely, 2^644466079 is an apocalyptic number.

644466079 is a deficient number, since it is larger than the sum of its proper divisors (1).

644466079 is an equidigital number, since it uses as much as digits as its factorization.

644466079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 870912, while the sum is 46.

The square root of 644466079 is about 25386.3364627510. The cubic root of 644466079 is about 863.7737886405.

The spelling of 644466079 in words is "six hundred forty-four million, four hundred sixty-six thousand, seventy-nine".