640224 has 120 divisors (see below), whose sum is σ = 2134440. Its totient is φ = 186624.

The previous prime is 640223. The next prime is 640229. The reversal of 640224 is 422046.

640224 is a `hidden beast` number, since 640 + 2 + 24 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 640197 and 640206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640223) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 33687 + ... + 33705.

It is an arithmetic number, because the mean of its divisors is an integer number (17787).

2⁶⁴⁰²²⁴ 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 640224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1067220).

640224 is an abundant number, since it is smaller than the sum of its proper divisors (1494216).

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

640224 is a wasteful number, since it uses less digits than its factorization.

640224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54 (or 37 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 640224 is about 800.1399877521. The cubic root of 640224 is about 86.1874404571.

The spelling of 640224 in words is "six hundred forty thousand, two hundred twenty-four".