638408 has 8 divisors (see below), whose sum is σ = 1197030. Its totient is φ = 319200.

The previous prime is 638371. The next prime is 638423. The reversal of 638408 is 804836.

It can be written as a sum of positive squares in only one way, i.e., 605284 + 33124 = 778^2 + 182^2 .

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

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, 39893 + ... + 39908.

2⁶³⁸⁴⁰⁸ is an apocalyptic number.

It is an amenable number.

638408 is a deficient number, since it is larger than the sum of its proper divisors (558622).

638408 is a wasteful number, since it uses less digits than its factorization.

638408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79807 (or 79803 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 638408 is about 799.0043804636. The cubic root of 638408 is about 86.1058728536.

The spelling of 638408 in words is "six hundred thirty-eight thousand, four hundred eight".