639809886 has 16 divisors (see below), whose sum is σ = 1282253184. Its totient is φ = 212831064.

The previous prime is 639809881. The next prime is 639809917. The reversal of 639809886 is 688908936.

639809886 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639809881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106560 + ... + 112403.

It is an arithmetic number, because the mean of its divisors is an integer number (80140824).

Almost surely, 2^639809886 is an apocalyptic number.

639809886 is an abundant number, since it is smaller than the sum of its proper divisors (642443298).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639809886 is a wasteful number, since it uses less digits than its factorization.

639809886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219455.

The product of its (nonzero) digits is 4478976, while the sum is 57.

The square root of 639809886 is about 25294.4635444202. The cubic root of 639809886 is about 861.6885366878.

The spelling of 639809886 in words is "six hundred thirty-nine million, eight hundred nine thousand, eight hundred eighty-six".