639400 has 48 divisors (see below), whose sum is σ = 1562400. Its totient is φ = 242880.

The previous prime is 639391. The next prime is 639433. The reversal of 639400 is 4936.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4531 + ... + 4669.

It is an arithmetic number, because the mean of its divisors is an integer number (32550).

2⁶³⁹⁴⁰⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781200).

639400 is an abundant number, since it is smaller than the sum of its proper divisors (923000).

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

639400 is a wasteful number, since it uses less digits than its factorization.

639400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178 (or 169 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 639400 is about 799.6249120682. The cubic root of 639400 is about 86.1504487475.

The spelling of 639400 in words is "six hundred thirty-nine thousand, four hundred".