644412079 has 2 divisors, whose sum is σ = 644412080. Its totient is φ = 644412078.

The previous prime is 644412071. The next prime is 644412133. The reversal of 644412079 is 970214446.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644412079 - 2³ = 644412071 is a prime.

It is a super-2 number, since 2×644412079² = 830533855122204482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644412071) 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, 322206039 + 322206040.

It is an arithmetic number, because the mean of its divisors is an integer number (322206040).

Almost surely, 2^644412079 is an apocalyptic number.

644412079 is a deficient number, since it is larger than the sum of its proper divisors (1).

644412079 is an equidigital number, since it uses as much as digits as its factorization.

644412079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 644412079 is about 25385.2728762170. The cubic root of 644412079 is about 863.7496626810.

The spelling of 644412079 in words is "six hundred forty-four million, four hundred twelve thousand, seventy-nine".