644063959 has 16 divisors (see below), whose sum is σ = 806457600. Its totient is φ = 499700160.

The previous prime is 644063951. The next prime is 644064007. The reversal of 644063959 is 959360446.

It is a cyclic number.

It is not a de Polignac number, because 644063959 - 2³ = 644063951 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 (644063951) 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, 9 + ... + 35890.

It is an arithmetic number, because the mean of its divisors is an integer number (50403600).

Almost surely, 2^644063959 is an apocalyptic number.

644063959 is a deficient number, since it is larger than the sum of its proper divisors (162393641).

644063959 is a wasteful number, since it uses less digits than its factorization.

644063959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36150.

The product of its (nonzero) digits is 699840, while the sum is 46.

The square root of 644063959 is about 25378.4152184489. The cubic root of 644063959 is about 863.5940983023.

The spelling of 644063959 in words is "six hundred forty-four million, sixty-three thousand, nine hundred fifty-nine".