638604 has 48 divisors (see below), whose sum is σ = 1699040. Its totient is φ = 209952.

The previous prime is 638587. The next prime is 638621. The reversal of 638604 is 406836.

It is an interprime number because it is at equal distance from previous prime (638587) and next prime (638621).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8712 + ... + 8784.

2⁶³⁸⁶⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (849520).

638604 is an abundant number, since it is smaller than the sum of its proper divisors (1060436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638604 is an equidigital number, since it uses as much as digits as its factorization.

638604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 638604 is about 799.1270236952. The cubic root of 638604 is about 86.1146838461.

The spelling of 638604 in words is "six hundred thirty-eight thousand, six hundred four".