640800 has 108 divisors (see below), whose sum is σ = 2285010. Its totient is φ = 168960.

The previous prime is 640793. The next prime is 640837. The reversal of 640800 is 8046.

It can be written as a sum of positive squares in 3 ways, for example, as 374544 + 266256 = 612^2 + 516^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7156 + ... + 7244.

2⁶⁴⁰⁸⁰⁰ is an apocalyptic number.

640800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is a pronic number, being equal to 800×801.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1142505).

640800 is an abundant number, since it is smaller than the sum of its proper divisors (1644210).

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

640800 is a wasteful number, since it uses less digits than its factorization.

640800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 640800 is about 800.4998438476. The cubic root of 640800 is about 86.2132798951.

Adding to 640800 its reverse (8046), we get a palindrome (648846).

It can be divided in two parts, 640 and 800, that multiplied together give a cube (512000 = 80³).

The spelling of 640800 in words is "six hundred forty thousand, eight hundred".