639854387 has 4 divisors (see below), whose sum is σ = 647563560. Its totient is φ = 632145216.

The previous prime is 639854377. The next prime is 639854399. The reversal of 639854387 is 783458936.

639854387 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 639854387 - 2¹⁰ = 639853363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639854377) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3854462 + ... + 3854627.

It is an arithmetic number, because the mean of its divisors is an integer number (161890890).

Almost surely, 2^639854387 is an apocalyptic number.

639854387 is a deficient number, since it is larger than the sum of its proper divisors (7709173).

639854387 is an equidigital number, since it uses as much as digits as its factorization.

639854387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7709172.

The product of its digits is 4354560, while the sum is 53.

The square root of 639854387 is about 25295.3431880257. The cubic root of 639854387 is about 861.7085140349.

The spelling of 639854387 in words is "six hundred thirty-nine million, eight hundred fifty-four thousand, three hundred eighty-seven".