638538 has 16 divisors (see below), whose sum is σ = 1318656. Its totient is φ = 205920.

The previous prime is 638527. The next prime is 638567. The reversal of 638538 is 835836.

It is a plaindrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 638499 and 638508.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1531 + ... + 1902.

It is an arithmetic number, because the mean of its divisors is an integer number (82416).

2⁶³⁸⁵³⁸ is an apocalyptic number.

638538 is an abundant number, since it is smaller than the sum of its proper divisors (680118).

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

638538 is a wasteful number, since it uses less digits than its factorization.

638538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3469.

The product of its digits is 17280, while the sum is 33.

The square root of 638538 is about 799.0857275662. The cubic root of 638538 is about 86.1117170806. Note that the first 3 decimals are identical.

It can be divided in two parts, 638 and 538, that added together give a triangular number (1176 = T₄₈).

The spelling of 638538 in words is "six hundred thirty-eight thousand, five hundred thirty-eight".