639551706 has 8 divisors (see below), whose sum is σ = 1279103424. Its totient is φ = 213183900.

The previous prime is 639551683. The next prime is 639551719. The reversal of 639551706 is 607155936.

It is a happy number.

639551706 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.

639551706 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53295970 + ... + 53295981.

It is an arithmetic number, because the mean of its divisors is an integer number (159887928).

Almost surely, 2^639551706 is an apocalyptic number.

639551706 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

639551706 is a wasteful number, since it uses less digits than its factorization.

639551706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106591956.

The product of its (nonzero) digits is 170100, while the sum is 42.

The square root of 639551706 is about 25289.3595411193. The cubic root of 639551706 is about 861.5726164839.

The spelling of 639551706 in words is "six hundred thirty-nine million, five hundred fifty-one thousand, seven hundred six".