638257 has 4 divisors (see below), whose sum is σ = 639856. Its totient is φ = 636660.

The previous prime is 638233. The next prime is 638263. The reversal of 638257 is 752836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 638257 - 2¹⁹ = 113969 is a prime.

It is a Duffinian number.

638257 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (638857) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 382 + ... + 1192.

It is an arithmetic number, because the mean of its divisors is an integer number (159964).

2⁶³⁸²⁵⁷ is an apocalyptic number.

It is an amenable number.

638257 is a deficient number, since it is larger than the sum of its proper divisors (1599).

638257 is an equidigital number, since it uses as much as digits as its factorization.

638257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1598.

The product of its digits is 10080, while the sum is 31.

The square root of 638257 is about 798.9098822771. The cubic root of 638257 is about 86.0990835631.

The spelling of 638257 in words is "six hundred thirty-eight thousand, two hundred fifty-seven".