644450573 has 6 divisors (see below), whose sum is σ = 697837194. Its totient is φ = 594877296.

The previous prime is 644450551. The next prime is 644450579. The reversal of 644450573 is 375054446.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 18550249 + 625900324 = 4307^2 + 25018^2 .

It is not a de Polignac number, because 644450573 - 2²⁸ = 376015117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644450579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1906490 + ... + 1906827.

It is an arithmetic number, because the mean of its divisors is an integer number (116306199).

Almost surely, 2^644450573 is an apocalyptic number.

It is an amenable number.

644450573 is a deficient number, since it is larger than the sum of its proper divisors (53386621).

644450573 is a wasteful number, since it uses less digits than its factorization.

644450573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3813343 (or 3813330 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 38.

The square root of 644450573 is about 25386.0310604080. The cubic root of 644450573 is about 863.7668610538.

The spelling of 644450573 in words is "six hundred forty-four million, four hundred fifty thousand, five hundred seventy-three".