7881238639 has 2 divisors, whose sum is σ = 7881238640. Its totient is φ = 7881238638.

The previous prime is 7881238601. The next prime is 7881238643. The reversal of 7881238639 is 9368321887.

7881238639 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 7881238639 - 2¹⁷ = 7881107567 is a prime.

It is a super-3 number, since 3×7881238639³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 7881238639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7881238699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3940619319 + 3940619320.

It is an arithmetic number, because the mean of its divisors is an integer number (3940619320).

Almost surely, 2^7881238639 is an apocalyptic number.

7881238639 is a deficient number, since it is larger than the sum of its proper divisors (1).

7881238639 is an equidigital number, since it uses as much as digits as its factorization.

7881238639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3483648, while the sum is 55.

The square root of 7881238639 is about 88776.3405362037. The cubic root of 7881238639 is about 1990.0538388505.

The spelling of 7881238639 in words is "seven billion, eight hundred eighty-one million, two hundred thirty-eight thousand, six hundred thirty-nine".