638849 has 4 divisors (see below), whose sum is σ = 644820. Its totient is φ = 632880.

The previous prime is 638839. The next prime is 638857. The reversal of 638849 is 948836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 368449 + 270400 = 607^2 + 520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638849 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638849.

It is not an unprimeable number, because it can be changed into a prime (638819) by changing a digit.

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, 2822 + ... + 3039.

It is an arithmetic number, because the mean of its divisors is an integer number (161205).

2⁶³⁸⁸⁴⁹ is an apocalyptic number.

It is an amenable number.

638849 is a deficient number, since it is larger than the sum of its proper divisors (5971).

638849 is a wasteful number, since it uses less digits than its factorization.

638849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5970.

The product of its digits is 41472, while the sum is 38.

The square root of 638849 is about 799.2803012711. The cubic root of 638849 is about 86.1256950518.

The spelling of 638849 in words is "six hundred thirty-eight thousand, eight hundred forty-nine".