6640444439 has 2 divisors, whose sum is σ = 6640444440. Its totient is φ = 6640444438.

The previous prime is 6640444429. The next prime is 6640444457. The reversal of 6640444439 is 9344440466.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6640444439 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6640444439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6640444429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320222219 + 3320222220.

It is an arithmetic number, because the mean of its divisors is an integer number (3320222220).

Almost surely, 2^6640444439 is an apocalyptic number.

6640444439 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640444439 is an equidigital number, since it uses as much as digits as its factorization.

6640444439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 995328, while the sum is 44.

The square root of 6640444439 is about 81488.9221857793. The cubic root of 6640444439 is about 1879.6012092681.

The spelling of 6640444439 in words is "six billion, six hundred forty million, four hundred forty-four thousand, four hundred thirty-nine".