6439919 has 2 divisors, whose sum is σ = 6439920. Its totient is φ = 6439918.

The previous prime is 6439903. The next prime is 6439921. The reversal of 6439919 is 9199346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6439919 - 2⁴ = 6439903 is a prime.

It is a super-2 number, since 2×6439919² = 82945113453122, which contains 22 as substring.

Together with 6439921, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6439949) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3219959 + 3219960.

It is an arithmetic number, because the mean of its divisors is an integer number (3219960).

Almost surely, 2^6439919 is an apocalyptic number.

6439919 is a deficient number, since it is larger than the sum of its proper divisors (1).

6439919 is an equidigital number, since it uses as much as digits as its factorization.

6439919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 41.

The square root of 6439919 is about 2537.6995488040. The cubic root of 6439919 is about 186.0487693443.

The spelling of 6439919 in words is "six million, four hundred thirty-nine thousand, nine hundred nineteen".