638128 has 10 divisors (see below), whose sum is σ = 1236404. Its totient is φ = 319056.

The previous prime is 638123. The next prime is 638147. The reversal of 638128 is 821836.

638128 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 junction number, because it is equal to n+sod(n) for n = 638096 and 638105.

It is not an unprimeable number, because it can be changed into a prime (638123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19926 + ... + 19957.

2⁶³⁸¹²⁸ is an apocalyptic number.

It is an amenable number.

638128 is a deficient number, since it is larger than the sum of its proper divisors (598276).

638128 is a wasteful number, since it uses less digits than its factorization.

638128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39891 (or 39885 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 638128 is about 798.8291431839. The cubic root of 638128 is about 86.0932825926.

The spelling of 638128 in words is "six hundred thirty-eight thousand, one hundred twenty-eight".