639309 has 8 divisors (see below), whose sum is σ = 929952. Its totient is φ = 387440.

The previous prime is 639307. The next prime is 639311. The reversal of 639309 is 903936.

It is an interprime number because it is at equal distance from previous prime (639307) and next prime (639311).

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 639309 - 2¹ = 639307 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639307) 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, 9654 + ... + 9719.

It is an arithmetic number, because the mean of its divisors is an integer number (116244).

2⁶³⁹³⁰⁹ is an apocalyptic number.

It is an amenable number.

639309 is a deficient number, since it is larger than the sum of its proper divisors (290643).

639309 is a wasteful number, since it uses less digits than its factorization.

639309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19387.

The product of its (nonzero) digits is 4374, while the sum is 30.

The square root of 639309 is about 799.5680083645. The cubic root of 639309 is about 86.1463615497.

The spelling of 639309 in words is "six hundred thirty-nine thousand, three hundred nine".