638251 has 4 divisors (see below), whose sum is σ = 641752. Its totient is φ = 634752.

The previous prime is 638233. The next prime is 638263. The reversal of 638251 is 152836.

It is a happy number.

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 638251 - 2⁷ = 638123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638201) 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, 1461 + ... + 1846.

It is an arithmetic number, because the mean of its divisors is an integer number (160438).

2⁶³⁸²⁵¹ is an apocalyptic number.

638251 is a deficient number, since it is larger than the sum of its proper divisors (3501).

638251 is a wasteful number, since it uses less digits than its factorization.

638251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3500.

The product of its digits is 1440, while the sum is 25.

The square root of 638251 is about 798.9061271514. The cubic root of 638251 is about 86.0988137679.

The spelling of 638251 in words is "six hundred thirty-eight thousand, two hundred fifty-one".