644340583 has 2 divisors, whose sum is σ = 644340584. Its totient is φ = 644340582.

The previous prime is 644340581. The next prime is 644340629. The reversal of 644340583 is 385043446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644340583 - 2¹ = 644340581 is a prime.

Together with 644340581, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644340581) 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, 322170291 + 322170292.

It is an arithmetic number, because the mean of its divisors is an integer number (322170292).

Almost surely, 2^644340583 is an apocalyptic number.

644340583 is a deficient number, since it is larger than the sum of its proper divisors (1).

644340583 is an equidigital number, since it uses as much as digits as its factorization.

644340583 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 138240, while the sum is 37.

The square root of 644340583 is about 25383.8646190843. The cubic root of 644340583 is about 863.7177178371.

The spelling of 644340583 in words is "six hundred forty-four million, three hundred forty thousand, five hundred eighty-three".