639876 has 12 divisors (see below), whose sum is σ = 1493072. Its totient is φ = 213288.

The previous prime is 639857. The next prime is 639907. The reversal of 639876 is 678936.

It is a tau number, because it is divible by the number of its divisors (12).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639876.

It is an unprimeable number.

639876 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26650 + ... + 26673.

2⁶³⁹⁸⁷⁶ is an apocalyptic number.

It is an amenable number.

639876 is an abundant number, since it is smaller than the sum of its proper divisors (853196).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639876 is a wasteful number, since it uses less digits than its factorization.

639876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53330 (or 53328 counting only the distinct ones).

The product of its digits is 54432, while the sum is 39.

The square root of 639876 is about 799.9224962457. The cubic root of 639876 is about 86.1718216188.

Subtracting 639876 from its reverse (678936), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 639876 in words is "six hundred thirty-nine thousand, eight hundred seventy-six".