639646 has 24 divisors (see below), whose sum is σ = 1145016. Its totient is φ = 267120.

The previous prime is 639637. The next prime is 639647. The reversal of 639646 is 646936.

639646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639647) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5925 + ... + 6031.

It is an arithmetic number, because the mean of its divisors is an integer number (47709).

2⁶³⁹⁶⁴⁶ is an apocalyptic number.

639646 is a deficient number, since it is larger than the sum of its proper divisors (505370).

639646 is a wasteful number, since it uses less digits than its factorization.

639646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 177 counting only the distinct ones).

The product of its digits is 23328, while the sum is 34.

The square root of 639646 is about 799.7787193968. The cubic root of 639646 is about 86.1614957150.

The spelling of 639646 in words is "six hundred thirty-nine thousand, six hundred forty-six".