638757 has 12 divisors (see below), whose sum is σ = 1054560. Its totient is φ = 364968.

The previous prime is 638719. The next prime is 638767. The reversal of 638757 is 757836.

It is not a de Polignac number, because 638757 - 2⁷ = 638629 is a prime.

638757 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638717) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5007 + ... + 5132.

It is an arithmetic number, because the mean of its divisors is an integer number (87880).

2⁶³⁸⁷⁵⁷ is an apocalyptic number.

It is an amenable number.

638757 is a deficient number, since it is larger than the sum of its proper divisors (415803).

638757 is a wasteful number, since it uses less digits than its factorization.

638757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10152 (or 10149 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 638757 is about 799.2227474240. Note that the first 3 decimals coincide. The cubic root of 638757 is about 86.1215605618.

The spelling of 638757 in words is "six hundred thirty-eight thousand, seven hundred fifty-seven".