638744 has 8 divisors (see below), whose sum is σ = 1197660. Its totient is φ = 319368.

The previous prime is 638719. The next prime is 638767. The reversal of 638744 is 447836.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 638744.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638744.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39914 + ... + 39929.

2⁶³⁸⁷⁴⁴ is an apocalyptic number.

It is an amenable number.

638744 is a deficient number, since it is larger than the sum of its proper divisors (558916).

638744 is a wasteful number, since it uses less digits than its factorization.

638744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79849 (or 79845 counting only the distinct ones).

The product of its digits is 16128, while the sum is 32.

The square root of 638744 is about 799.2146144810. The cubic root of 638744 is about 86.1209763084.

The spelling of 638744 in words is "six hundred thirty-eight thousand, seven hundred forty-four".