645580800 has 288 divisors, whose sum is σ = 2376410400. Its totient is φ = 171786240.

The previous prime is 645580781. The next prime is 645580843. The reversal of 645580800 is 8085546.

It is a happy number.

645580800 is a `hidden beast` number, since 645 + 5 + 8 + 0 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 23 ways as a sum of consecutive naturals, for example, 1382167 + ... + 1382633.

It is an arithmetic number, because the mean of its divisors is an integer number (8251425).

Almost surely, 2^645580800 is an apocalyptic number.

645580800 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 645580800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1188205200).

645580800 is an abundant number, since it is smaller than the sum of its proper divisors (1730829600).

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

645580800 is a wasteful number, since it uses less digits than its factorization.

645580800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 36.

The square root of 645580800 is about 25408.2821143028. The cubic root of 645580800 is about 864.2715196019.

The spelling of 645580800 in words is "six hundred forty-five million, five hundred eighty thousand, eight hundred".