644523416 has 16 divisors (see below), whose sum is σ = 1208760840. Its totient is φ = 322187200.

The previous prime is 644523391. The next prime is 644523421. The reversal of 644523416 is 614325446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48716 + ... + 60516.

Almost surely, 2^644523416 is an apocalyptic number.

It is an amenable number.

644523416 is a deficient number, since it is larger than the sum of its proper divisors (564237424).

644523416 is a wasteful number, since it uses less digits than its factorization.

644523416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18634 (or 18630 counting only the distinct ones).

The product of its digits is 69120, while the sum is 35.

The square root of 644523416 is about 25387.4657262201. The cubic root of 644523416 is about 863.7994040197.

The spelling of 644523416 in words is "six hundred forty-four million, five hundred twenty-three thousand, four hundred sixteen".