6439799381 has 2 divisors, whose sum is σ = 6439799382. Its totient is φ = 6439799380.

The previous prime is 6439799351. The next prime is 6439799383. The reversal of 6439799381 is 1839979346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5036173156 + 1403626225 = 70966^2 + 37465^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6439799381 is a prime.

It is a super-2 number, since 2×6439799381² = 82942032135055966322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 6439799383, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 6439799381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6439799383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3219899690 + 3219899691.

It is an arithmetic number, because the mean of its divisors is an integer number (3219899691).

Almost surely, 2^6439799381 is an apocalyptic number.

It is an amenable number.

6439799381 is a deficient number, since it is larger than the sum of its proper divisors (1).

6439799381 is an equidigital number, since it uses as much as digits as its factorization.

6439799381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8817984, while the sum is 59.

The square root of 6439799381 is about 80248.3606125384. The cubic root of 6439799381 is about 1860.4761740927.

The spelling of 6439799381 in words is "six billion, four hundred thirty-nine million, seven hundred ninety-nine thousand, three hundred eighty-one".