639943529 has 16 divisors (see below), whose sum is σ = 694552320. Its totient is φ = 587408640.

The previous prime is 639943517. The next prime is 639943531. The reversal of 639943529 is 925349936.

It is a cyclic number.

It is not a de Polignac number, because 639943529 - 2²⁰ = 638894953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639943589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108599 + ... + 114339.

It is an arithmetic number, because the mean of its divisors is an integer number (43409520).

Almost surely, 2^639943529 is an apocalyptic number.

It is an amenable number.

639943529 is a deficient number, since it is larger than the sum of its proper divisors (54608791).

639943529 is a wasteful number, since it uses less digits than its factorization.

639943529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5920.

The product of its digits is 1574640, while the sum is 50.

The square root of 639943529 is about 25297.1051505899. The cubic root of 639943529 is about 861.7485287919.

The spelling of 639943529 in words is "six hundred thirty-nine million, nine hundred forty-three thousand, five hundred twenty-nine".