638867 has 4 divisors (see below), whose sum is σ = 641256. Its totient is φ = 636480.

The previous prime is 638861. The next prime is 638893. The reversal of 638867 is 768836.

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 638867 - 2¹⁴ = 622483 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638867.

It is not an unprimeable number, because it can be changed into a prime (638861) 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, 734 + ... + 1347.

It is an arithmetic number, because the mean of its divisors is an integer number (160314).

2⁶³⁸⁸⁶⁷ is an apocalyptic number.

638867 is a deficient number, since it is larger than the sum of its proper divisors (2389).

638867 is a wasteful number, since it uses less digits than its factorization.

638867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2388.

The product of its digits is 48384, while the sum is 38.

The square root of 638867 is about 799.2915613216. The cubic root of 638867 is about 86.1265039273.

The spelling of 638867 in words is "six hundred thirty-eight thousand, eight hundred sixty-seven".