638724 has 48 divisors (see below), whose sum is σ = 1645056. Its totient is φ = 192000.

The previous prime is 638719. The next prime is 638767. The reversal of 638724 is 427836.

638724 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a d-powerful number, because it can be written as 6⁶ + 3⁷ + 7² + 8 + 2¹⁹ + 4⁸ .

It is a junction number, because it is equal to n+sod(n) for n = 638691 and 638700.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6274 + ... + 6374.

It is an arithmetic number, because the mean of its divisors is an integer number (34272).

2⁶³⁸⁷²⁴ 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 638724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (822528).

638724 is an abundant number, since it is smaller than the sum of its proper divisors (1006332).

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

638724 is a wasteful number, since it uses less digits than its factorization.

638724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156 (or 154 counting only the distinct ones).

The product of its digits is 8064, while the sum is 30.

The square root of 638724 is about 799.2021020993. The cubic root of 638724 is about 86.1200774415.

The spelling of 638724 in words is "six hundred thirty-eight thousand, seven hundred twenty-four".