640522240 has 96 divisors (see below), whose sum is σ = 1560293280. Its totient is φ = 252313600.

The previous prime is 640522237. The next prime is 640522247. The reversal of 640522240 is 42225046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640522247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726600 + ... + 727480.

It is an arithmetic number, because the mean of its divisors is an integer number (16253055).

Almost surely, 2^640522240 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 640522240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (780146640).

640522240 is an abundant number, since it is smaller than the sum of its proper divisors (919771040).

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

640522240 is an equidigital number, since it uses as much as digits as its factorization.

640522240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 979 (or 959 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

The square root of 640522240 is about 25308.5408508669. The cubic root of 640522240 is about 862.0082147784.

Adding to 640522240 its reverse (42225046), we get a palindrome (682747286).

The spelling of 640522240 in words is "six hundred forty million, five hundred twenty-two thousand, two hundred forty".