638536 has 8 divisors (see below), whose sum is σ = 1197270. Its totient is φ = 319264.

The previous prime is 638527. The next prime is 638567. The reversal of 638536 is 635836.

638536 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 630436 + 8100 = 794^2 + 90^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 638498 and 638507.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39901 + ... + 39916.

2⁶³⁸⁵³⁶ is an apocalyptic number.

It is an amenable number.

638536 is a deficient number, since it is larger than the sum of its proper divisors (558734).

638536 is a wasteful number, since it uses less digits than its factorization.

638536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79823 (or 79819 counting only the distinct ones).

The product of its digits is 12960, while the sum is 31.

The square root of 638536 is about 799.0844761350. The cubic root of 638536 is about 86.1116271754. Note that the first 3 decimals are identical.

The spelling of 638536 in words is "six hundred thirty-eight thousand, five hundred thirty-six".