638309 has 8 divisors (see below), whose sum is σ = 740928. Its totient is φ = 538560.

The previous prime is 638303. The next prime is 638317. The reversal of 638309 is 903836.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638309 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638303) 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, 212 + ... + 1149.

It is an arithmetic number, because the mean of its divisors is an integer number (92616).

2⁶³⁸³⁰⁹ is an apocalyptic number.

It is an amenable number.

638309 is a deficient number, since it is larger than the sum of its proper divisors (102619).

638309 is a wasteful number, since it uses less digits than its factorization.

638309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1435.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 638309 is about 798.9424259607. The cubic root of 638309 is about 86.1014217178.

The spelling of 638309 in words is "six hundred thirty-eight thousand, three hundred nine".