640320 has 112 divisors (see below), whose sum is σ = 2194560. Its totient is φ = 157696.

The previous prime is 640307. The next prime is 640333. The reversal of 640320 is 23046.

It is an interprime number because it is at equal distance from previous prime (640307) and next prime (640333).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 640320.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640320.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22066 + ... + 22094.

2⁶⁴⁰³²⁰ is an apocalyptic number.

640320 is a gapful number since it is divisible by the number (60) 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 640320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1097280).

640320 is an abundant number, since it is smaller than the sum of its proper divisors (1554240).

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

640320 is a wasteful number, since it uses less digits than its factorization.

640320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 640320 is about 800.1999750062. The cubic root of 640320 is about 86.1917481061.

Adding to 640320 its reverse (23046), we get a palindrome (663366).

The spelling of 640320 in words is "six hundred forty thousand, three hundred twenty".