644545005 has 32 divisors (see below), whose sum is σ = 1114210944. Its totient is φ = 316283136.

The previous prime is 644544997. The next prime is 644545043. The reversal of 644545005 is 500545446.

It is not a de Polignac number, because 644545005 - 2³ = 644544997 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 56602 + ... + 67028.

It is an arithmetic number, because the mean of its divisors is an integer number (34819092).

Almost surely, 2^644545005 is an apocalyptic number.

644545005 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

644545005 is a deficient number, since it is larger than the sum of its proper divisors (469665939).

644545005 is a wasteful number, since it uses less digits than its factorization.

644545005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10765.

The product of its (nonzero) digits is 48000, while the sum is 33.

The square root of 644545005 is about 25387.8909127954. The cubic root of 644545005 is about 863.8090485398.

The spelling of 644545005 in words is "six hundred forty-four million, five hundred forty-five thousand, five".