638911 has 24 divisors (see below), whose sum is σ = 861840. Its totient is φ = 467712.

The previous prime is 638893. The next prime is 638923. The reversal of 638911 is 119836.

It is a happy number.

It is not a de Polignac number, because 638911 - 2¹¹ = 636863 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638911.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638971) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10800 + ... + 10858.

It is an arithmetic number, because the mean of its divisors is an integer number (35910).

2⁶³⁸⁹¹¹ is an apocalyptic number.

638911 is a deficient number, since it is larger than the sum of its proper divisors (222929).

638911 is a wasteful number, since it uses less digits than its factorization.

638911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 96 counting only the distinct ones).

The product of its digits is 1296, while the sum is 28.

The square root of 638911 is about 799.3190852219. The cubic root of 638911 is about 86.1284811146.

It can be divided in two parts, 6389 and 11, that added together give a square (6400 = 80²).

The spelling of 638911 in words is "six hundred thirty-eight thousand, nine hundred eleven".