638738 has 8 divisors (see below), whose sum is σ = 961740. Its totient is φ = 318160.

The previous prime is 638719. The next prime is 638767. The reversal of 638738 is 837836.

It can be written as a sum of positive squares in 2 ways, for example, as 597529 + 41209 = 773^2 + 203^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 638698 and 638707.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638738.

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 3 ways as a sum of consecutive naturals, for example, 368 + ... + 1188.

2⁶³⁸⁷³⁸ is an apocalyptic number.

638738 is a deficient number, since it is larger than the sum of its proper divisors (323002).

638738 is a wasteful number, since it uses less digits than its factorization.

638738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212.

The product of its digits is 24192, while the sum is 35.

The square root of 638738 is about 799.2108607871. The cubic root of 638738 is about 86.1207066503.

The spelling of 638738 in words is "six hundred thirty-eight thousand, seven hundred thirty-eight".