638929 has 4 divisors (see below), whose sum is σ = 648000. Its totient is φ = 629860.

The previous prime is 638923. The next prime is 638933. The reversal of 638929 is 929836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638929 - 2⁷ = 638801 is a prime.

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

It is a Duffinian number.

638929 is a lucky number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4429 + ... + 4570.

It is an arithmetic number, because the mean of its divisors is an integer number (162000).

2⁶³⁸⁹²⁹ is an apocalyptic number.

It is an amenable number.

638929 is a deficient number, since it is larger than the sum of its proper divisors (9071).

638929 is an equidigital number, since it uses as much as digits as its factorization.

638929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9070.

The product of its digits is 23328, while the sum is 37.

The square root of 638929 is about 799.3303447261. The cubic root of 638929 is about 86.1292899378.

The spelling of 638929 in words is "six hundred thirty-eight thousand, nine hundred twenty-nine".