640584 has 96 divisors (see below), whose sum is σ = 2096640. Its totient is φ = 172800.

The previous prime is 640583. The next prime is 640589. The reversal of 640584 is 485046.

It is a super-2 number, since 2×640584² = 820695722112, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640583) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15604 + ... + 15644.

It is an arithmetic number, because the mean of its divisors is an integer number (21840).

2⁶⁴⁰⁵⁸⁴ 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 640584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1048320).

640584 is an abundant number, since it is smaller than the sum of its proper divisors (1456056).

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

640584 is a wasteful number, since it uses less digits than its factorization.

640584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 640584 is about 800.3649167723. The cubic root of 640584 is about 86.2035919211.

The spelling of 640584 in words is "six hundred forty thousand, five hundred eighty-four".