6640859 has 4 divisors (see below), whose sum is σ = 6929616. Its totient is φ = 6352104.

The previous prime is 6640849. The next prime is 6640889. The reversal of 6640859 is 9580466.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6640859 - 2²⁰ = 5592283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6640849) 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 3 ways as a sum of consecutive naturals, for example, 144344 + ... + 144389.

It is an arithmetic number, because the mean of its divisors is an integer number (1732404).

Almost surely, 2^6640859 is an apocalyptic number.

6640859 is a deficient number, since it is larger than the sum of its proper divisors (288757).

6640859 is a wasteful number, since it uses less digits than its factorization.

6640859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288756.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 6640859 is about 2576.9864182801. The cubic root of 6640859 is about 187.9640322772.

The spelling of 6640859 in words is "six million, six hundred forty thousand, eight hundred fifty-nine".