644003005 has 16 divisors (see below), whose sum is σ = 814870080. Its totient is φ = 487251072.

The previous prime is 644002991. The next prime is 644003011. The reversal of 644003005 is 500300446.

It is a cyclic number.

It is not a de Polignac number, because 644003005 - 2⁹ = 644002493 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53122 + ... + 64108.

It is an arithmetic number, because the mean of its divisors is an integer number (50929380).

Almost surely, 2^644003005 is an apocalyptic number.

It is an amenable number.

644003005 is a deficient number, since it is larger than the sum of its proper divisors (170867075).

644003005 is a wasteful number, since it uses less digits than its factorization.

644003005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11628.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 644003005 is about 25377.2142876242. The cubic root of 644003005 is about 863.5668540229.

The spelling of 644003005 in words is "six hundred forty-four million, three thousand, five".