6440939 has 2 divisors, whose sum is σ = 6440940. Its totient is φ = 6440938.

The previous prime is 6440933. The next prime is 6440947. The reversal of 6440939 is 9390446.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6440939 - 2⁸ = 6440683 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 6440899 and 6440908.

It is not a weakly prime, because it can be changed into another prime (6440933) 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 as a sum of consecutive naturals, namely, 3220469 + 3220470.

It is an arithmetic number, because the mean of its divisors is an integer number (3220470).

Almost surely, 2^6440939 is an apocalyptic number.

6440939 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440939 is an equidigital number, since it uses as much as digits as its factorization.

6440939 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 6440939 is about 2537.9005102643. The cubic root of 6440939 is about 186.0585913999.

The spelling of 6440939 in words is "six million, four hundred forty thousand, nine hundred thirty-nine".