639425671 has 2 divisors, whose sum is σ = 639425672. Its totient is φ = 639425670.

The previous prime is 639425629. The next prime is 639425701. The reversal of 639425671 is 176524936.

639425671 is digitally balanced in base 2, 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 639425671 - 2¹¹ = 639423623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639422671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319712835 + 319712836.

It is an arithmetic number, because the mean of its divisors is an integer number (319712836).

Almost surely, 2^639425671 is an apocalyptic number.

639425671 is a deficient number, since it is larger than the sum of its proper divisors (1).

639425671 is an equidigital number, since it uses as much as digits as its factorization.

639425671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 43.

The square root of 639425671 is about 25286.8675600597. The cubic root of 639425671 is about 861.5160167138.

The spelling of 639425671 in words is "six hundred thirty-nine million, four hundred twenty-five thousand, six hundred seventy-one".