6644845785 has 16 divisors (see below), whose sum is σ = 10725842304. Its totient is φ = 3512554752.

The previous prime is 6644845783. The next prime is 6644845793. The reversal of 6644845785 is 5875484466.

It is not a de Polignac number, because 6644845785 - 2¹ = 6644845783 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6644845783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1958437 + ... + 1961826.

It is an arithmetic number, because the mean of its divisors is an integer number (670365144).

Almost surely, 2^6644845785 is an apocalyptic number.

It is an amenable number.

6644845785 is a deficient number, since it is larger than the sum of its proper divisors (4080996519).

6644845785 is a wasteful number, since it uses less digits than its factorization.

6644845785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3920384.

The product of its digits is 25804800, while the sum is 57.

The square root of 6644845785 is about 81515.9235057789. The cubic root of 6644845785 is about 1880.0163897206.

The spelling of 6644845785 in words is "six billion, six hundred forty-four million, eight hundred forty-five thousand, seven hundred eighty-five".