644310645 has 16 divisors (see below), whose sum is σ = 1124615232. Its totient is φ = 312392960.

The previous prime is 644310617. The next prime is 644310677. The reversal of 644310645 is 546013446.

It is not a de Polignac number, because 644310645 - 2¹⁰ = 644309621 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1952292 + ... + 1952621.

It is an arithmetic number, because the mean of its divisors is an integer number (70288452).

Almost surely, 2^644310645 is an apocalyptic number.

It is an amenable number.

644310645 is a deficient number, since it is larger than the sum of its proper divisors (480304587).

644310645 is a wasteful number, since it uses less digits than its factorization.

644310645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3904932.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 644310645 is about 25383.2749069146. The cubic root of 644310645 is about 863.7043406563.

The spelling of 644310645 in words is "six hundred forty-four million, three hundred ten thousand, six hundred forty-five".