644793697 has 16 divisors (see below), whose sum is σ = 693781200. Its totient is φ = 597104640.

The previous prime is 644793691. The next prime is 644793701. The reversal of 644793697 is 796397446.

644793697 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 11566801 + 633226896 = 3401^2 + 25164^2 .

It is a cyclic number.

It is not a de Polignac number, because 644793697 - 2³ = 644793689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644793691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 345547 + ... + 347407.

It is an arithmetic number, because the mean of its divisors is an integer number (43361325).

Almost surely, 2^644793697 is an apocalyptic number.

It is an amenable number.

644793697 is a deficient number, since it is larger than the sum of its proper divisors (48987503).

644793697 is a wasteful number, since it uses less digits than its factorization.

644793697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196.

The product of its digits is 6858432, while the sum is 55.

The square root of 644793697 is about 25392.7882872283. The cubic root of 644793697 is about 863.9201319527.

The spelling of 644793697 in words is "six hundred forty-four million, seven hundred ninety-three thousand, six hundred ninety-seven".