639536 has 10 divisors (see below), whose sum is σ = 1239132. Its totient is φ = 319760.

The previous prime is 639533. The next prime is 639547. The reversal of 639536 is 635936.

It is an Ulam number.

It is a d-powerful number, because it can be written as 6⁷ + 3⁶ + 5⁷ + 9² + 3⁶ + 6⁷ .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639536.

It is not an unprimeable number, because it can be changed into a prime (639533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19970 + ... + 20001.

2⁶³⁹⁵³⁶ is an apocalyptic number.

It is an amenable number.

639536 is a deficient number, since it is larger than the sum of its proper divisors (599596).

639536 is a wasteful number, since it uses less digits than its factorization.

639536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39979 (or 39973 counting only the distinct ones).

The product of its digits is 14580, while the sum is 32.

The square root of 639536 is about 799.7099474184. The cubic root of 639536 is about 86.1565563642.

Subtracting from 639536 its reverse (635936), we obtain a square (3600 = 60²).

The spelling of 639536 in words is "six hundred thirty-nine thousand, five hundred thirty-six".