639228439 has 2 divisors, whose sum is σ = 639228440. Its totient is φ = 639228438.

The previous prime is 639228413. The next prime is 639228521. The reversal of 639228439 is 934822936.

639228439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639228439 - 2⁷ = 639228311 is a prime.

It is a super-2 number, since 2×639228439² = 817225994452753442, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639223439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319614219 + 319614220.

It is an arithmetic number, because the mean of its divisors is an integer number (319614220).

Almost surely, 2^639228439 is an apocalyptic number.

639228439 is a deficient number, since it is larger than the sum of its proper divisors (1).

639228439 is an equidigital number, since it uses as much as digits as its factorization.

639228439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 46.

The square root of 639228439 is about 25282.9673693576. The cubic root of 639228439 is about 861.4274288824.

It can be divided in two parts, 63922 and 8439, that added together give a square (72361 = 269²).

The spelling of 639228439 in words is "six hundred thirty-nine million, two hundred twenty-eight thousand, four hundred thirty-nine".