638783 has 4 divisors (see below), whose sum is σ = 660840. Its totient is φ = 616728.

The previous prime is 638767. The next prime is 638801. The reversal of 638783 is 387836.

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

It is a cyclic number.

It is not a de Polignac number, because 638783 - 2⁴ = 638767 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

638783 is a modest number, since divided by 783 gives 638 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (637783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10985 + ... + 11042.

It is an arithmetic number, because the mean of its divisors is an integer number (165210).

2⁶³⁸⁷⁸³ is an apocalyptic number.

638783 is a deficient number, since it is larger than the sum of its proper divisors (22057).

638783 is a wasteful number, since it uses less digits than its factorization.

638783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22056.

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

The square root of 638783 is about 799.2390130618. The cubic root of 638783 is about 86.1227290449.

The spelling of 638783 in words is "six hundred thirty-eight thousand, seven hundred eighty-three".