638464 has 40 divisors (see below), whose sum is σ = 1350360. Its totient is φ = 301056.

The previous prime is 638459. The next prime is 638467. The reversal of 638464 is 464836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14827 + ... + 14869.

It is an arithmetic number, because the mean of its divisors is an integer number (33759).

2⁶³⁸⁴⁶⁴ is an apocalyptic number.

638464 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (675180).

638464 is an abundant number, since it is smaller than the sum of its proper divisors (711896).

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

638464 is an equidigital number, since it uses as much as digits as its factorization.

638464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 74 counting only the distinct ones).

The product of its digits is 13824, while the sum is 31.

The square root of 638464 is about 799.0394233078. The cubic root of 638464 is about 86.1083904640.

The spelling of 638464 in words is "six hundred thirty-eight thousand, four hundred sixty-four".