639398 has 4 divisors (see below), whose sum is σ = 959100. Its totient is φ = 319698.

The previous prime is 639391. The next prime is 639433. The reversal of 639398 is 893936.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 639398.

It is not an unprimeable number, because it can be changed into a prime (639391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159848 + ... + 159851.

It is an arithmetic number, because the mean of its divisors is an integer number (239775).

2⁶³⁹³⁹⁸ is an apocalyptic number.

639398 is a deficient number, since it is larger than the sum of its proper divisors (319702).

639398 is a wasteful number, since it uses less digits than its factorization.

639398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319701.

The product of its digits is 34992, while the sum is 38.

The square root of 639398 is about 799.6236614808. The cubic root of 639398 is about 86.1503589231.

Subtracting from 639398 its product of digits (34992), we obtain a palindrome (604406).

The spelling of 639398 in words is "six hundred thirty-nine thousand, three hundred ninety-eight".