638388 has 48 divisors (see below), whose sum is σ = 1733760. Its totient is φ = 202752.

The previous prime is 638371. The next prime is 638423. The reversal of 638388 is 883836.

638388 is nontrivially palindromic in base 11.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638388.

It is an unprimeable number.

638388 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 15 ways as a sum of consecutive naturals, for example, 2356 + ... + 2612.

It is an arithmetic number, because the mean of its divisors is an integer number (36120).

2⁶³⁸³⁸⁸ 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 638388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (866880).

638388 is an abundant number, since it is smaller than the sum of its proper divisors (1095372).

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

638388 is a wasteful number, since it uses less digits than its factorization.

638388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 285 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 638388 is about 798.9918647896. The cubic root of 638388 is about 86.1049736713.

The spelling of 638388 in words is "six hundred thirty-eight thousand, three hundred eighty-eight".