639843604 has 6 divisors (see below), whose sum is σ = 1119726314. Its totient is φ = 319921800.

The previous prime is 639843599. The next prime is 639843619. The reversal of 639843604 is 406348936.

It can be written as a sum of positive squares in only one way, i.e., 472192900 + 167650704 = 21730^2 + 12948^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79980447 + ... + 79980454.

Almost surely, 2^639843604 is an apocalyptic number.

It is an amenable number.

639843604 is a deficient number, since it is larger than the sum of its proper divisors (479882710).

639843604 is a wasteful number, since it uses less digits than its factorization.

639843604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159960905 (or 159960903 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 43.

The square root of 639843604 is about 25295.1300451292. The cubic root of 639843604 is about 861.7036734257.

The spelling of 639843604 in words is "six hundred thirty-nine million, eight hundred forty-three thousand, six hundred four".