638908 has 12 divisors (see below), whose sum is σ = 1124872. Its totient is φ = 317520.

The previous prime is 638893. The next prime is 638923. The reversal of 638908 is 809836.

It is an interprime number because it is at equal distance from previous prime (638893) and next prime (638923).

It is a congruent number.

It is an unprimeable number.

638908 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466 + ... + 1222.

2⁶³⁸⁹⁰⁸ is an apocalyptic number.

It is an amenable number.

638908 is a deficient number, since it is larger than the sum of its proper divisors (485964).

638908 is a wasteful number, since it uses less digits than its factorization.

638908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972 (or 970 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 638908 is about 799.3172086225. The cubic root of 638908 is about 86.1283463093.

The spelling of 638908 in words is "six hundred thirty-eight thousand, nine hundred eight".