640302320 has 80 divisors (see below), whose sum is σ = 1709146560. Its totient is φ = 218529792.

The previous prime is 640302301. The next prime is 640302323. The reversal of 640302320 is 23203046.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 640302292 and 640302301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640302323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 125744 + ... + 130736.

It is an arithmetic number, because the mean of its divisors is an integer number (21364332).

Almost surely, 2^640302320 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 640302320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (854573280).

640302320 is an abundant number, since it is smaller than the sum of its proper divisors (1068844240).

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

640302320 is a wasteful number, since it uses less digits than its factorization.

640302320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5242 (or 5236 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 640302320 is about 25304.1956995278. The cubic root of 640302320 is about 861.9095481305.

Adding to 640302320 its reverse (23203046), we get a palindrome (663505366).

The spelling of 640302320 in words is "six hundred forty million, three hundred two thousand, three hundred twenty".