644457695 has 16 divisors (see below), whose sum is σ = 885139968. Its totient is φ = 441257760.

The previous prime is 644457689. The next prime is 644457703. The reversal of 644457695 is 596754446.

It is not a de Polignac number, because 644457695 - 2¹⁴ = 644441311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 10862 + ... + 37508.

It is an arithmetic number, because the mean of its divisors is an integer number (55321248).

Almost surely, 2^644457695 is an apocalyptic number.

644457695 is a deficient number, since it is larger than the sum of its proper divisors (240682273).

644457695 is a wasteful number, since it uses less digits than its factorization.

644457695 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27350.

The product of its digits is 3628800, while the sum is 50.

The square root of 644457695 is about 25386.1713340157. The cubic root of 644457695 is about 863.7700429502.

The spelling of 644457695 in words is "six hundred forty-four million, four hundred fifty-seven thousand, six hundred ninety-five".