638215 has 4 divisors (see below), whose sum is σ = 765864. Its totient is φ = 510568.

The previous prime is 638201. The next prime is 638233. The reversal of 638215 is 512836.

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 638215 - 2¹³ = 630023 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638215.

It is a congruent number.

It is an unprimeable number.

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, 63817 + ... + 63826.

It is an arithmetic number, because the mean of its divisors is an integer number (191466).

2⁶³⁸²¹⁵ is an apocalyptic number.

638215 is a deficient number, since it is larger than the sum of its proper divisors (127649).

638215 is a wasteful number, since it uses less digits than its factorization.

638215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127648.

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

The square root of 638215 is about 798.8835960264. The cubic root of 638215 is about 86.0971949609.

The spelling of 638215 in words is "six hundred thirty-eight thousand, two hundred fifteen".