638040 has 64 divisors (see below), whose sum is σ = 2066400. Its totient is φ = 156672.

The previous prime is 638023. The next prime is 638047. The reversal of 638040 is 40836.

638040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 637998 and 638016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638047) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1356 + ... + 1764.

2⁶³⁸⁰⁴⁰ is an apocalyptic number.

638040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1033200).

638040 is an abundant number, since it is smaller than the sum of its proper divisors (1428360).

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

638040 is a wasteful number, since it uses less digits than its factorization.

638040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436 (or 432 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 638040 is about 798.7740606705. The cubic root of 638040 is about 86.0893248928.

Adding to 638040 its reverse (40836), we get a palindrome (678876).

The spelling of 638040 in words is "six hundred thirty-eight thousand, forty".