638903 has 4 divisors (see below), whose sum is σ = 654528. Its totient is φ = 623280.

The previous prime is 638893. The next prime is 638923. The reversal of 638903 is 309836.

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 638903 - 2⁶ = 638839 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638923) 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, 7751 + ... + 7832.

It is an arithmetic number, because the mean of its divisors is an integer number (163632).

2⁶³⁸⁹⁰³ is an apocalyptic number.

638903 is a deficient number, since it is larger than the sum of its proper divisors (15625).

638903 is a wasteful number, since it uses less digits than its factorization.

638903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15624.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 638903 is about 799.3140809469. The cubic root of 638903 is about 86.1281216327.

The spelling of 638903 in words is "six hundred thirty-eight thousand, nine hundred three".