639670 has 16 divisors (see below), whose sum is σ = 1176768. Its totient is φ = 250240.

The previous prime is 639647. The next prime is 639671. The reversal of 639670 is 76936.

639670 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 (639671) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 211 + ... + 1150.

It is an arithmetic number, because the mean of its divisors is an integer number (73548).

2⁶³⁹⁶⁷⁰ is an apocalyptic number.

639670 is a deficient number, since it is larger than the sum of its proper divisors (537098).

639670 is a wasteful number, since it uses less digits than its factorization.

639670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 639670 is about 799.7937234062. The cubic root of 639670 is about 86.1625733163.

The spelling of 639670 in words is "six hundred thirty-nine thousand, six hundred seventy".