640868800 has 168 divisors, whose sum is σ = 1853287632. Its totient is φ = 215040000.

The previous prime is 640868759. The next prime is 640868843. The reversal of 640868800 is 8868046.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 227400 + ... + 230200.

It is an arithmetic number, because the mean of its divisors is an integer number (11031474).

Almost surely, 2^640868800 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 640868800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (926643816).

640868800 is an abundant number, since it is smaller than the sum of its proper divisors (1212418832).

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

640868800 is a wasteful number, since it uses less digits than its factorization.

640868800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2847 (or 2832 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 40.

The square root of 640868800 is about 25315.3866255288. The cubic root of 640868800 is about 862.1636523710.

The spelling of 640868800 in words is "six hundred forty million, eight hundred sixty-eight thousand, eight hundred".