638209 has 8 divisors (see below), whose sum is σ = 749952. Its totient is φ = 535440.

The previous prime is 638201. The next prime is 638233. The reversal of 638209 is 902836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 638209 - 2³ = 638201 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 7 ways as a sum of consecutive naturals, for example, 2089 + ... + 2374.

It is an arithmetic number, because the mean of its divisors is an integer number (93744).

2⁶³⁸²⁰⁹ is an apocalyptic number.

It is an amenable number.

638209 is a deficient number, since it is larger than the sum of its proper divisors (111743).

638209 is a wasteful number, since it uses less digits than its factorization.

638209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4487.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 638209 is about 798.8798407771. The cubic root of 638209 is about 86.0969251538.

The spelling of 638209 in words is "six hundred thirty-eight thousand, two hundred nine".