639889439 has 16 divisors (see below), whose sum is σ = 741303360. Its totient is φ = 541017600.

The previous prime is 639889427. The next prime is 639889477. The reversal of 639889439 is 934988936.

639889439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 639889439 - 2⁴ = 639889423 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639889409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205607 + ... + 208695.

It is an arithmetic number, because the mean of its divisors is an integer number (46331460).

Almost surely, 2^639889439 is an apocalyptic number.

639889439 is a deficient number, since it is larger than the sum of its proper divisors (101413921).

639889439 is a wasteful number, since it uses less digits than its factorization.

639889439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3490.

The product of its digits is 10077696, while the sum is 59.

The square root of 639889439 is about 25296.0360333393. The cubic root of 639889439 is about 861.7242488937.

The spelling of 639889439 in words is "six hundred thirty-nine million, eight hundred eighty-nine thousand, four hundred thirty-nine".