6440644635 has 8 divisors (see below), whose sum is σ = 10305031440. Its totient is φ = 3435010464.

The previous prime is 6440644631. The next prime is 6440644663. The reversal of 6440644635 is 5364460446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6440644635 - 2² = 6440644631 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6440644631) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 214688140 + ... + 214688169.

It is an arithmetic number, because the mean of its divisors is an integer number (1288128930).

Almost surely, 2^6440644635 is an apocalyptic number.

6440644635 is a deficient number, since it is larger than the sum of its proper divisors (3864386805).

6440644635 is a wasteful number, since it uses less digits than its factorization.

6440644635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429376317.

The product of its (nonzero) digits is 829440, while the sum is 42.

The square root of 6440644635 is about 80253.6269273857. The cubic root of 6440644635 is about 1860.5575692851.

The spelling of 6440644635 in words is "six billion, four hundred forty million, six hundred forty-four thousand, six hundred thirty-five".