638887 has 4 divisors (see below), whose sum is σ = 643896. Its totient is φ = 633880.

The previous prime is 638861. The next prime is 638893. The reversal of 638887 is 788836.

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 638887 - 2¹⁹ = 114599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638857) 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, 2308 + ... + 2569.

It is an arithmetic number, because the mean of its divisors is an integer number (160974).

2⁶³⁸⁸⁸⁷ is an apocalyptic number.

638887 is a deficient number, since it is larger than the sum of its proper divisors (5009).

638887 is a wasteful number, since it uses less digits than its factorization.

638887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5008.

The product of its digits is 64512, while the sum is 40.

The square root of 638887 is about 799.3040723029. The cubic root of 638887 is about 86.1274026600.

The spelling of 638887 in words is "six hundred thirty-eight thousand, eight hundred eighty-seven".