640780800 has 480 divisors, whose sum is σ = 2429469504. Its totient is φ = 147456000.

The previous prime is 640780747. The next prime is 640780817. The reversal of 640780800 is 8087046.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15628780 + ... + 15628820.

Almost surely, 2^640780800 is an apocalyptic number.

640780800 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 640780800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1214734752).

640780800 is an abundant number, since it is smaller than the sum of its proper divisors (1788688704).

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

640780800 is a wasteful number, since it uses less digits than its factorization.

640780800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 640780800 is about 25313.6484924635. The cubic root of 640780800 is about 862.1241883006.

The spelling of 640780800 in words is "six hundred forty million, seven hundred eighty thousand, eight hundred".