639382891 has 8 divisors (see below), whose sum is σ = 731198720. Its totient is φ = 547685928.

The previous prime is 639382883. The next prime is 639382921. The reversal of 639382891 is 198283936.

639382891 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 not a de Polignac number, because 639382891 - 2³ = 639382883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639302891) 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, 17871 + ... + 39976.

It is an arithmetic number, because the mean of its divisors is an integer number (91399840).

Almost surely, 2^639382891 is an apocalyptic number.

639382891 is a deficient number, since it is larger than the sum of its proper divisors (91815829).

639382891 is a wasteful number, since it uses less digits than its factorization.

639382891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59433.

The product of its digits is 559872, while the sum is 49.

The square root of 639382891 is about 25286.0216522884. The cubic root of 639382891 is about 861.4968033901.

The spelling of 639382891 in words is "six hundred thirty-nine million, three hundred eighty-two thousand, eight hundred ninety-one".