639879389 has 8 divisors (see below), whose sum is σ = 669218112. Its totient is φ = 610667200.

The previous prime is 639879353. The next prime is 639879391. The reversal of 639879389 is 983978936.

639879389 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639879389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639879349) 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, 21212 + ... + 41589.

It is an arithmetic number, because the mean of its divisors is an integer number (83652264).

Almost surely, 2^639879389 is an apocalyptic number.

It is an amenable number.

639879389 is a deficient number, since it is larger than the sum of its proper divisors (29338723).

639879389 is a wasteful number, since it uses less digits than its factorization.

639879389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63267.

The product of its digits is 17635968, while the sum is 62.

The square root of 639879389 is about 25295.8373848347. The cubic root of 639879389 is about 861.7197375029.

The spelling of 639879389 in words is "six hundred thirty-nine million, eight hundred seventy-nine thousand, three hundred eighty-nine".