638381 has 4 divisors (see below), whose sum is σ = 672000. Its totient is φ = 604764.

The previous prime is 638371. The next prime is 638423. The reversal of 638381 is 183836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638381 - 2⁶ = 638317 is a prime.

It is a super-2 number, since 2×638381² = 815060602322, which contains 22 as substring.

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

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16781 + ... + 16818.

It is an arithmetic number, because the mean of its divisors is an integer number (168000).

2⁶³⁸³⁸¹ is an apocalyptic number.

It is an amenable number.

638381 is a deficient number, since it is larger than the sum of its proper divisors (33619).

638381 is a wasteful number, since it uses less digits than its factorization.

638381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33618.

The product of its digits is 3456, while the sum is 29.

The square root of 638381 is about 798.9874842574. The cubic root of 638381 is about 86.1046589531.

The spelling of 638381 in words is "six hundred thirty-eight thousand, three hundred eighty-one".