639803306 has 4 divisors (see below), whose sum is σ = 959704962. Its totient is φ = 319901652.

The previous prime is 639803303. The next prime is 639803309. The reversal of 639803306 is 603308936.

639803306 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 an interprime number because it is at equal distance from previous prime (639803303) and next prime (639803309).

It can be written as a sum of positive squares in only one way, i.e., 393030625 + 246772681 = 19825^2 + 15709^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 639803306.

It is not an unprimeable number, because it can be changed into a prime (639803303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159950825 + ... + 159950828.

Almost surely, 2^639803306 is an apocalyptic number.

639803306 is a deficient number, since it is larger than the sum of its proper divisors (319901656).

639803306 is a wasteful number, since it uses less digits than its factorization.

639803306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319901655.

The product of its (nonzero) digits is 69984, while the sum is 38.

The square root of 639803306 is about 25294.3334760970. Note that the first 3 decimals coincide. The cubic root of 639803306 is about 861.6855827218.

The spelling of 639803306 in words is "six hundred thirty-nine million, eight hundred three thousand, three hundred six".