640500 has 96 divisors (see below), whose sum is σ = 2166528. Its totient is φ = 144000.

The previous prime is 640499. The next prime is 640529. The reversal of 640500 is 5046.

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 640500.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10470 + ... + 10530.

It is an arithmetic number, because the mean of its divisors is an integer number (22568).

2⁶⁴⁰⁵⁰⁰ is an apocalyptic number.

640500 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 640500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1083264).

640500 is an abundant number, since it is smaller than the sum of its proper divisors (1526028).

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

640500 is a wasteful number, since it uses less digits than its factorization.

640500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 640500 is about 800.3124389887. The cubic root of 640500 is about 86.1998237876.

Adding to 640500 its reverse (5046), we get a palindrome (645546).

The spelling of 640500 in words is "six hundred forty thousand, five hundred".